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Limits

Class 11th Mathematics RS Aggarwal Solution
Exercise 27a
  1. Evaluate lim_ { x arrow2 } (5-x)
  2. Evaluate lim_ { x arrow1 } ( 6x^{2} - 4x+3 )
  3. Evaluate lim_ { x arrow3 } ( { x^{2} + 9 }/{x+3} )
  4. Evaluate lim_ { x arrow3 } ( { x^{2} - 4x }/{x-2} )
  5. Evaluate lim_ { x arrow5 } ( { x^{2} - 25 }/{x-5} )
  6. Evaluate lim_ { x arrow1 } ( { x^{3} - 1 }/{x-1} )
  7. Evaluate lim_ { x arrow-2 } ( { x^{3} + 8 }/{x+2} )
  8. Evaluate lim_ { x arrow3 } ( { x^{4} - 81 }/{x-3} )
  9. Evaluate lim_ { x arrow3 } ( { x^{2} - 4x+3 }/{ x^{2} - 2x-3 } )…
  10. Evaluate lim_ { x arrow {1}/{2} } ( frac { 4x^{2} - 1 }/{2x-1} )…
  11. Evaluate lim_ { x arrow4 } ( { x^{3} - 64 }/{ x^{2} - 16 } )
  12. Evaluate lim_ { x arrow2 } ( { x^{5} - 32 }/{ x^{3} - 8 } )
  13. Evaluate lim_ { x arrowa } ( {x^{5/2}-a^{5/2}}/{x-a} )
  14. Evaluate lim_ { x arrowa } { { (x+2)^{5/3} - (a+2)^{5/3} }/{x-a} }…
  15. Evaluate lim_ { x arrow1 } ( { x^{n} - 1 }/{x-1} )
  16. Evaluate lim_ { x arrowa } ( { root {x} - sqrt{a} }/{x-a} )
  17. Evaluate lim_ { h arrow0 } ( { root {x+h} - sqrt{x} }/{h} )
  18. Evaluate lim_ { h arrow0 } {1}/{h} { frac {1}/{ root {x+h} } - frac {1}/{…
  19. Evaluate lim_ { x arrow0 } ( { root {1+x}-1 }/{x} )
  20. Evaluate lim_ { x arrow0 } ( { root {2-x} - sqrt{2+x} }/{x} )
  21. Evaluate lim_ { x arrow0 } ( { root { 1+x+x^{2} } - 1 }/{x} )…
  22. Evaluate lim_ { x arrow0 } ( { root {3-x}-1 }/{2-x} )
  23. Evaluate lim_ { x arrow0 } ( {2x}/{ root {a+x} - sqrt{a-x} } )…
  24. Evaluate lim_ { x arrow1 } ( { root {3+x} - sqrt{5-x} }/{ x^{2} - 1 } )…
  25. Evaluate lim_ { x arrow2 } ( { x^{2} - 4 }/{ root {x+2} - sqrt{3x-2} } )…
  26. Evaluate lim_ { x arrow4 } ( { 3 - root {5+x} }/{ 1 - sqrt{5-x} } )…
  27. Evaluate lim_ { x arrow0 } ( { root {a+x} - sqrt{a} }/{ x sqrt { a (a+x) }…
  28. Evaluate lim_ { x arrow0 } ( { root { 1+x^{2} } - sqrt{1+x} }/{ sqrt {…
  29. Evaluate lim_ { x arrow1 } ( { x^{4} - 3x^{2} + 2 }/{ x^{3} - 5x^{2} + 3x+1…
  30. Evaluate lim_ { x arrow2 } ( { 3^{x} - 3^{3-x} - 12 }/{ 3^{3-x} - 3^{x/2} }…
  31. Evaluate lim_ { x arrow0 } ( { e^{4x} - 1 }/{x} )
  32. Evaluate lim_ { x arrow0 } ( { e^{2+x} - e^{2} }/{x} )
  33. Evaluate lim_ { x arrow4 } ( { e^{x} - e^{4} }/{x-4} )
  34. Evaluate lim_ { x arrow0 } ( { e^{3x} - e^{2x} }/{x} )
  35. Evaluate lim_ { x arrow0 } ( { e^{x} - x-1 }/{x} )
  36. Evaluate lim_ { x arrow0 } ( { e^{bx} - e^{ax} }/{x} ) , 0
  37. Evaluate lim_ { x arrow0 } ( { a^{x} - b^{x} }/{x} )
  38. Evaluate lim_ { x arrow0 } ( { a^{x} - a^{-x} }/{x} )
  39. Evaluate lim_ { x arrow0 } ( { 2^{x} - 1 }/{x} )
  40. Evaluate lim_ { x arrow0 } ( { 3^{2+x} - 9 }/{x} )
Exercise 27b
  1. lim_ { x arrow0 } {sin4x}/{6x} Evaluate the following limits:
  2. lim_ { x arrow0 } {sin5x}/{sin8x} Evaluate the following limits:…
  3. lim_ { x arrow0 } {tan3x}/{tan5x} Evaluate the following limits:…
  4. lim_ { x arrow0 } {tanalpha x}/{tanbeta x} Evaluate the following limits:…
  5. lim_ { x arrow0 } {sin4x}/{tan7x} Evaluate the following limits:…
  6. lim_ { x arrow0 } {tan3x}/{sin4x} Evaluate the following limits:…
  7. lim_ { x arrow0 } {sinmx}/{tannx} Evaluate the following limits:…
  8. lim_ { x arrow0 } {sinx-2sin3x+sin5x}/{x} Evaluate the following limits:…
  9. lim_ { x arrow pi /6 } { (2sin^{2}x+sinx-1) }/{ (2sin^{2}x-3sinx+1) }…
  10. lim_ { x arrow0 } { (sin2x+3x) }/{ (2x+sin3x) } Evaluate the following…
  11. lim_ { x arrow0 } { (tan2x-x) }/{ (3x-tanx) } Evaluate the following limits:…
  12. lim_ { x arrow0 } { ( x^{2} - tan2x ) }/{tanx} Evaluate the following…
  13. lim_ { x arrow0 } {xcosx+sinx}/{ x^{2} + tanx } Evaluate the following…
  14. lim_ { x arrow0 } {tanx-sinx}/{sin^{3}x} Evaluate the following limits:…
  15. lim_ { x arrow0 } xcosecx Evaluate the following limits:
  16. lim_ { x arrow0 } (xcot2x) Evaluate the following limits:
  17. lim_ { x arrow0 } {sinxcosx}/{3x} Evaluate the following limits:…
  18. lim_ { x arrow0 } { sin (x/4) }/{x} Evaluate the following limits:…
  19. lim_ { x arrow0 } { tan (x/2) }/{3x} Evaluate the following limits:…
  20. lim_ { x arrow0 } {1-cosx}/{sin^{2}x} Evaluate the following limits:…
  21. lim_ { x arrow0 } {1-cos3x}/{ x^{2} } Evaluate the following limits:…
  22. lim_ { x arrow0 } {1-cosx}/{sin^{2}2x} Evaluate the following limits:…
  23. lim_ { x arrow0 } {1-cos2x}/{3tan^{2}x} Evaluate the following limits:…
  24. lim_ { x arrow0 } { (1-cos4x) }/{ (1-cos6x) } Evaluate the following limits:…
  25. lim_ { x arrow0 } {1-cossinx}/{1-cosnx} Evaluate the following limits:…
  26. lim_ { x arrow0 } {2sinx-sin2x}/{ x^{3} } Evaluate the following limits:…
  27. lim_ { x arrow0 } { (tanx-sinx) }/{ x^{3} } Evaluate the following limits:…
  28. lim_ { x arrow0 } {tan2x-sin2x}/{ x^{3} } Evaluate the following limits:…
  29. lim_ { x arrow0 } {cosecx-cotx}/{x} Evaluate the following limits:…
  30. lim_ { x arrow0 } {cot2x-cosec2x}/{x} Evaluate the following limits:…
  31. lim_ { x arrow0 } { sin2x (1-cos2x) }/{ x^{3} } Evaluate the following…
  32. lim_ { x arrow { pi }/{4} } frac {sec^{2}x-2}/{tanx-1} Evaluate the…
  33. lim_ { x arrow { pi }/{4} } frac {cosec^{2}x-2}/{cotx-1} Evaluate the…
  34. lim_ { x arrow { pi }/{4} } frac {1-tanx}/{ x - frac { pi }/{4} } Evaluate…
  35. lim_ { x arrow pi } {sin3x-3sinx}/{ ( pi-x ) ^{3} } Evaluate the following…
  36. lim_ { x arrow { pi }/{2} } frac {1+cos2x}/{ ( pi-2x ) ^{2} } Evaluate the…
  37. lim_ { x arrowa } { (cosx-cosa) }/{ (x-a) } Evaluate the following limits:…
  38. lim_ { x arrowa } { (sinx-sina) }/{ (x-a) } Evaluate the following limits:…
  39. lim_ { x arrowa } { (sinx-sina) }/{ ( root {x} - sqrt{a} ) } Evaluate the…
  40. lim_ { x arrow0 } {sin5x-sin3x}/{sinx} Evaluate the following limits:…
  41. lim_ { x arrow0 } { (cos3x-cos5x) }/{ x^{2} } Evaluate the following limits:…
  42. lim_ { x arrow0 } { (sin3x+sin5x) }/{ (sin6x-sin4x) } Evaluate the following…
  43. lim_ { x arrow0 } { [ sin (2+x) - sin (2-x) ] }/{x} Evaluate the following…
  44. lim_ { x arrow0 } { (1-cos2x) }/{ (cos2x-cos8x) } Evaluate the following…
  45. lim_ { x arrow { pi }/{2} } ( frac { pi }/{2} - x ) tanx Evaluate the…
  46. lim_ { x arrow0 } { ( root {1+2x} - sqrt{1-2x} }/{sinx} Evaluate the…
  47. lim_ { h arrow0 } { (a+h)^{2}sin (a+h) - a^{2}sina }/{h} Evaluate the…
  48. lim_ { h arrow0 } { ( e^{3+x} - sinx-e^{3} ) }/{x} Evaluate the following…
  49. lim_ { x arrow0 } { (e^{tanx}-1) }/{tanx} Evaluate the following limits:…
  50. lim_ { x arrow0 } { (e^{tanx}-1) }/{x} Evaluate the following limits:…
  51. lim_ { x arrow0 } {9x+xcosx}/{bsinx} Evaluate the following limits:…
  52. lim_ { x arrow0 } {sinax+bx}/{ax+sinbx} , a , b , a+b not equal 0 Evaluate…
  53. lim_ { x arrow0 } { sin ( pi -x ) }/{ pi ( pi-x ) } Evaluate the following…
  54. lim_ { x arrow { pi }/{2} } frac {tan2x}/{ x - frac { pi }/{2} } Evaluate…
  55. lim_ { x arrow0 } {cos2x-1}/{cosx-1} Evaluate the following limits:…
  56. lim_ { x arrow0 } (cosecx-cotx) Evaluate the following limits:
  57. Evaluate the following limits:
  58. lim_ { x arrow0 } {1-cosmx}/{1-cosnx} Evaluate the following limits:…
  59. lim_ { x arrow0 } {sin^{2}mx}/{sin^{2}nx} Evaluate the following limits:…
  60. lim_ { x arrow0 } {sin2x+sin3x}/{2x+sin3x} Evaluate the following limits:…
  61. lim_ { x arrow0 } {sec4x-sec2x}/{sec3x-secx} Evaluate the following limits:…
  62. lim_ { x arrow0 } { root {2} - sqrt{1+cosx} }/{sin^{2}x} Evaluate the…
  63. lim_ { x arrow0 } { root {1+sinx} - sqrt{1-cosx} }/{x} Evaluate the…
  64. lim_ { x arrow { pi }/{6} } frac { 2 - root {3} cosx-sinx }/{ ( 6x - pi )…
  65. lim_ { x arrow0 } {cosax-cosbx}/{coscx-1} Evaluate the following limits:…
  66. lim_ { x arrowa } {cosx-cosa}/{cotx-cota} Evaluate the following limits:…
  67. lim_ { x arrow { pi }/{4} } frac {tan^{3}x-tanx}/{ cos ( x + frac { pi…
  68. lim_ { x arrow { pi }/{2} } frac { root {2} - sqrt{1+sinx} }/{ sqrt{2}…
  69. lim_ { x arrow { pi }/{6} } frac {cot^{2}x-3}/{cosecx-2} Evaluate the…
  70. lim_ { x arrow pi } { root {2+cosx}-1 }/{ ( pi-x ) ^{2} } Evaluate the…
  71. lim_ { x arrow { pi }/{4} } frac {1-tanx}/{ 1 - root {2} sinx } Evaluate…
  72. lim_ { x arrow { pi }/{6} } frac {2sin^{2}x+sinx-1}/{2sin^{2}x-3sinx+1}…
Exercise 27c
  1. If f (x) = |x|-3 , find lim_ { x arrow3 } f (x)
  2. Let f (x) = { { {x}/{|x|}x not equal 0 } { 0 , x = 0 } Show that lim_ { x…
  3. Let Show that lim_ { x arrow3 } f (x) does not exist.
  4. Let f (x) = { {ll} { 1+x^{2} , } & { 0 less than equal to x leq1 } { 2-x , }…
  5. Let f (x) = { {ll} { {x-|x|}/{x} , } & { x not equal 0 } { 2 , } & { x = 0 }…
  6. Let f (x) = { {ll} { 5x-4 , } & { 0Find lim_ { x arrow1 } f (x)…
  7. Let f (x) = { { 4x-5 , x less than equal to 2 } { x-a , x>2 } If lim_ { x…
  8. Let f (x) = { {r} { {3x}/{|x|+2x} , x not equal 0 } { 0 , x = 0 } Show that…
  9. Let f (x) = { { cosx, x geater than or equal to 0 } { x+k , x<0 } Find the…
  10. Show that lim_ { x arrow0 } {1}/{x} does not exist.
  11. Show that lim_ { x arrow0 } {1}/{|x|} = infinity .
  12. Show that lim_ { x arrow0 } e^{-1/x} does not exist.
  13. Show that lim_ { x arrow0 } sin {1}/{x} does not exist.
  14. Show that lim_ { x arrow0 } {x}/{|x|} does not exist.
  15. Let f (x) = { {ll} { {kcosx}/{ pi -2x } , } & { x not equal frac { pi…

Exercise 27a
Question 1.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have




Thus, the value of 3.



Question 2.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have


12-4(1)+3


0


Thus, the value of 0.



Question 3.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have




=3


Thus, the value of 3.



Question 4.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have





Thus, the value of -3.



Question 5.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have






Thus, the value of -10.



Question 6.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


and


x3-y3=(x-y)(x2+xy+y2)


As , we have






Thus, the value of3.



Question 7.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


and


x3+y3=(x+y)(x2-xy+y2)


As , we have




4-4+4


4


Thus, the value of4



Question 8.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


and


As , we have







= 18 × 6

= 108


Thus, the value of108.


Question 9.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


and


As , we have





Thus, the value of.



Question 10.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have





Thus, the value of 2.



Question 11.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


and


x3-y3=(x-y)(x2+xy+y2)


As , we have






Thus, the value ofis 6.



Question 12.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


=mym-1


As , we have






Thus, the value ofis



Question 13.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


=mym-1


As , we have




Thus, the value ofis



Question 14.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


=mym-1


As , we have





Thus, the value ofis



Question 15.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


=mym-1


As , we have



Thus, the value ofis n.



Question 16.

Evaluate


Answer:

To evaluate:


Formula used:


We have,


=mym-1


As , we have




Thus, the value ofis



Question 17.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis



Question 18.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis 0.



Question 19.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis



Question 20.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get






Thus, the value ofis



Question 21.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis



Question 22.

Evaluate


Answer:

To evaluate:


Formula used:


We have,



As , we have



Thus, the value of .



Question 23.

Evaluate


Answer:

To evaluate:


Formula used:


Multiplying numerator and denominator by







Thus, the value ofis



Question 24.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis



Question 25.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get







Thus, the value ofis -8.



Question 26.

Evaluate


Answer:

To evaluate:


Formula used:


Multiplying numerator and denominator with conjugates of numerator and denominator i.e






Thus, the value ofis



Question 27.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get






Thus, the value ofis



Question 28.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





-1


Thus, the value ofis -1.



Question 29.

Evaluate


Answer:

To Evaluate:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



Therefore,



Hence,




Question 30.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get






Thus, the value ofis



Question 31.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis 4.



Question 32.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis e2.



Question 33.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis e4.



Question 34.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get




3-2


1


Thus, the value ofis 1.



Question 35.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get




1-1


0


Thus, the value ofis 0.



Question 36.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get




b-a


Thus, the value ofis b-a.



Question 37.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get






Thus, the value ofis.



Question 38.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis.



Question 39.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis



Question 40.

Evaluate


Answer:

To evaluate:


Formula used:


L'Hospital's rule


Let f(x) and g(x) be two functions which are differentiable on an open interval I except at a point a where


then



As , we have



This represents an indeterminate form. Thus applying L'Hospital's rule, we get





Thus, the value ofis




Exercise 27b
Question 1.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfied any one from 7 indeterminate forms.


In this Case, indeterminate Form is


Formula used: = 1


So = ) = =


Therefore, =



Question 2.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfied any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1


So = ) = =


Therefore, =



Question 3.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfied any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1


So = ) = =


Therefore, =



Question 4.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfied any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 ‘


So = ) = =


Therefore, =



Question 5.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 and = 1


So = ) = =


Therefore, =



Question 6.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 and = 1


So = ) = =


Therefore, =



Question 7.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 and = 1


So = ) = =


Therefore, =



Question 8.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, inderterminate Form is


Formula used: = 1


So = - + ) = - + )


By using the above formula, we have


- + ) = 1 - 2 + 5 = 0


Therefore, = 0



Question 9.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 or we can used L hospital Rule,


So, by using the rule, Differentiate numerator and denominator


= = = -3


Therefore, = -3



Question 10.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 or we can used L hospital Rule,


So, by using the above formula, we have


Divide numerator and denominator by x,


= = = = = 1


ALTER:by using the rule, Differentiate numerator and denominator


= = 1


Therefore, = 1



Question 11.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 or we can used L hospital Rule,


So, by using the above formula, we have


Divide numerator and denominator by x,


= = = = =


Therefore, =



Question 12.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 or we can used L hospital Rule,


So, by using the above formula, we have


Divide numerator and denominator by x,


= = = = = -2


Therefore, = -2



Question 13.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1 and = 1


So, by using the above formula, we have


Divide numerator and denominator by x,


= = = = 2


Therefore, = 2



Question 14.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


NOTE : tan x – sin x = – sin x = = sin x ()


= =


Divide numerator and denominator by x2,


=


Formula used: = 1/2 and = 1 or we can used L hospital Rule,


So, by using the above formula, we have


= =


Therefore, =


Question 15.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form are 0


Formula used: = 1


So, by using the above formula, we have


= = 1


Therefore, = 1



Question 16.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is 0


Formula used: = 1


So, by using the above formula, we have


= =


Therefore, =



Question 17.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1


So, by using the above formula, we have


= =


Therefore, =



Question 18.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1


So, by using the above formula, we have


= =


Therefore, =



Question 19.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = 1


So, by using the above formula, we have


= = [Divide and multiply with 2 on denominator]


Therefore, =



Question 20.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


[NOTE: 1 – cos x = 2 sin2(x/2)]


Formula used: = 1


So, by using the above formula, we have


=


Divide numerator and denominator by x2, we have


= = = = =


[NOTE: = ]


Therefore, =



Question 21.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: =


So, by using the above formula, we have


= =


Therefore, =



Question 22.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = and = 1


Divide numerator and denominator by x2, we have


So, by using the above formula, we have


= =


Therefore, =



Question 23.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: = and = 1


Divide numerator and denominator by x2, we have


So, by using the above formula, we have


= = =


Therefore, =



Question 24.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: =


Divide numerator and denominator by x2, we have


So, by using the above formula, we have


= = = =


Therefore, =



Question 25.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


Formula used: =


Divide numerator and denominator by m2 and n2, we have


So, by using the above formula, we have


= =


Therefore, =



Question 26.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


We know that sin 2x = 2 sin x cosx


Formula used: = and =


So, by using the above formula, we have


= = = = = 1


Therefore, = 1



Question 27.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


NOTE : tan x – sin x = – sin x = = sin x ()


= =


Formula used: = 1/2 and = 1 or we can used L hospital Rule,


So, by using the above formula, we have


=


Therefore, =


Question 28.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


= = = = 4


Therefore,=



Question 29.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


cosec x – cot x = (1 – cos x)/sinx


= = =


Formula used: = 1/2 and = 1


= =


Therefore, =


Question 30.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form are


cosec 2x – cot 2x = (1 – cos 2x)/sin 2x


= = =


Formula used: = 1/2 and = 1


= = =


Therefore, =


Question 31.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


= =


Formula used: = 1/2 and = 1


= 4


Therefore, =


Question 32.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


By using L hospital Rule,


Differtiate both sides w.r.t x


So = So = = = 2


Therefore, =



Question 33.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


By using L hospital Rule,


Differtiate both sides w.r.t x


So = = = = 2


Therefore, =



Question 34.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Formis


By using L hospital Rule,


Differtiate both sides w.r.t x


So = = = -2


Therefore, =



Question 35.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


By using L hospital Rule,


Differtiate both sides w.r.t x


So =


Again, indeterminate Form is


So, Differtiate both sides w.r.t x again, we have


=


Again, indeterminate Form is


So, Differtiate both sides w.r.t x again, we have


= = = = - 4


Therefore, =



Question 36.

Evaluate the following limits:




Answer:

To Find: Limits


NOTE: First Check the form of imit. Used this method if the limit is satisfying any one from 7 indeterminate form.


In this Case, indeterminate Form is


By using L hospital Rule,


Differtiate both sides w.r.t x


So = = =


Again, indeterminate Form is


So, Differtiate both sides w.r.t x again, we have


= = = = =


Therefore, =



Question 37.

Evaluate the following limits:




Answer:


[]






= -sin (a)




Question 38.

Evaluate the following limits:




Answer:





=cosa




Question 39.

Evaluate the following limits:




Answer:


[Multiply and divide by √x-√a]




=2√a×cosa


=2√acosa




Question 40.

Evaluate the following limits:




Answer:



= 2 × 1




Question 41.

Evaluate the following limits:




Answer:






=8




Question 42.

Evaluate the following limits:




Answer:





= 4




Question 43.

Evaluate the following limits:




Answer:





=2cos2




Question 44.

Evaluate the following limits:




Answer:







Question 45.

Evaluate the following limits:




Answer:





=1




Question 46.

Evaluate the following limits:




Answer:






=2




Question 47.

Evaluate the following limits:




Answer:





=2a2cosa+2asina




Question 48.

Evaluate the following limits:




Answer:




=-1+e3




Question 49.

Evaluate the following limits:




Answer:


As x tends to 0, tan(x) also tends to zero,


So,



=1




Question 50.

Evaluate the following limits:




Answer:




=1×1


=1




Question 51.

Evaluate the following limits:




Answer:








Question 52.

Evaluate the following limits:




Answer:







=1




Question 53.

Evaluate the following limits:




Answer:









Question 54.

Evaluate the following limits:




Answer:


As x tends to, tends to zero.


Let,





=2




Question 55.

Evaluate the following limits:




Answer:





=4




Question 56.

Evaluate the following limits:




Answer:






=0




Question 57.

Evaluate the following limits:




Answer:







Question 58.

Evaluate the following limits:




Answer:






Question 59.

Evaluate the following limits:




Answer:






Question 60.

Evaluate the following limits:




Answer:




=1




Question 61.

Evaluate the following limits:




Answer:












Question 62.

Evaluate the following limits:




Answer:











Question 63.

Evaluate the following limits:




Answer:







=1




Question 64.

Evaluate the following limits:




Answer:









Question 65.

Evaluate the following limits:




Answer:







Question 66.

Evaluate the following limits:




Answer:




=sin3a




Question 67.

Evaluate the following limits:




Answer:






Question 68.

Evaluate the following limits:




Answer:




Let,







Question 69.

Evaluate the following limits:




Answer:





=4




Question 70.

Evaluate the following limits:




Answer:




Let,






Question 71.

Evaluate the following limits:




Answer:


Let,




= 2




Question 72.

Evaluate the following limits:




Answer:



= -3





Exercise 27c
Question 1.

If , find


Answer:

Left Hand Limit(L.H.L.):





= - ( 3 - 3)


= 0


Right Hand Limit(R.H.L.):





= 3-3


= 0


Since,



We can say that the limit exists and




Question 2.

Let

Show that does not exist.


Answer:

Left Hand Limit(L.H.L.):





= -1


Right Hand Limit(R.H.L.):





=1


Since does not exist



Question 3.

Let

Show that does not exist.


Answer:

Left Hand Limit(L.H.L.):





= -1


Right Hand Limit(R.H.L.):





= 1



Thus, does not exist.



Question 4.

Let

Show that does not exist.


Answer:

Left Hand Limit(L.H.L.):



= 1 + (1)2


= 1 + 1


= 2


Right Hand Limit(R.H.L.):



= 2 – (1)


= 2 – 1


=1



Thus, does not exist.



Question 5.

Let

Show that does not exist


Answer:

Left Hand Limit(L.H.L.):







= 2


Right Hand Limit(R.H.L.):






= 0



Thus, does not exist.



Question 6.

Let

Find


Answer:

Left Hand Limit(L.H.L.):



= 5(1) – 4


= 5 – 4


= 1


Right Hand Limit(R.H.L.):



= 4 (1)3 – 3 (1)


= 4 – 3


= 1



Thus, = 1



Question 7.

Let

If exists then find the value of a.


Answer:

Left Hand Limit(L.H.L.):



= 4 (2) – 5


= 8 – 5


= 3


Right Hand Limit(R.H.L.):



= 2 – a


Since it exists,



→ 3 = 2 – a


→ a = 2 – 3


→ a = -1



Question 8.

Let

Show that does not exist.


Answer:

Left Hand Limit(L.H.L.):






= 3


Right Hand Limit(R.H.L.):






= 1


Since



Thus, does not exist.



Question 9.

Let

Find the value of k for which exist.


Answer:

Left Hand Limit(L.H.L.):



= 0 + k


= k


Right Hand Limit(R.H.L.):



= cos (0)


= 1


It is given that exists. Therefore,



→ k = 1



Question 10.

Show that does not exist.


Answer:

Let x = 0+h for x tending to 0+


Since x→ 0, h also tends to 0


Right Hand Limit(R.H.L.):






=


=


Let x=0 -h for x tending to 0-


Since x→0, h also tends to 0.


Left Hand Limit(L.H.L.):






=


= - ∞


Since,



Thus, does not exist.



Question 11.

Show that .


Answer:

Let x = 0 + h, when x is tends to 0+


Since x tends to 0, h will also tend to 0.


Right Hand Limit(R.H.L):






=


=∞


Let x = 0 - h, when x is tends to 0-


Since x tends to 0, h will also tend to 0.


Left Hand Limit(L.H.L.):







=


= ∞


Thus,



.



Question 12.

Show that does not exist.


Answer:

Left Hand Limit(L.H.L.):





=


= e



Right Hand Limit(R.H.L.):




= e-∞


=


[ Formula , anything to the power infinity is also infinity. Thus ]


=0


Since



does not exist.



Question 13.

Show that does not exist.


Answer:

Let x = 0 + h, when x is tends to 0+


Since x tends to 0, h will also tend to 0.


Right Hand Limit(R.H.L.):





=


= sin ∞


= ∞


Let x = 0 - h, when x is tends to 0-


Since x tends to 0, h will also tend to 0.


Left Hand Limit(L.H.L.):





=


=


= - sin ∞


= -∞


Since,



does not exist.



Question 14.

Show that does not exist.


Answer:

Left Hand Limit(L.H.L.):





= -1


Right Hand Limit(R.H.L.):





= 1


Since



Thus, does not exist.



Question 15.

Let

If , find the value of k.


Answer:


Let




or,


or , h → 0


Putting this in the original sum,






[ Applying formula ]


= -k × 1


= -k



It is given that


∴ -k = 3


→ k = -3