NCERT Solutions for Class 12 Maths Chapter 5 – Continuity and Differentiability Ex 5.5
Page No 178:
Question 1:
Differentiate the function with respect to x.

Answer:

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Question 2:
Differentiate the function with respect to x.

Answer:

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Question 3:
Differentiate the function with respect to x.

Answer:

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Question 4:
Differentiate the function with respect to x.

Answer:

u = xx
Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

v = 2sin x
Taking logarithm on both the sides with respect to x, we obtain

Differentiating both sides with respect to x, we obtain


Question 5:
Differentiate the function with respect to x.

Answer:

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Question 6:
Differentiate the function with respect to x.

Answer:


Differentiating both sides with respect to x, we obtain


Differentiating both sides with respect to x, we obtain

Therefore, from (1), (2), and (3), we obtain

Question 7:
Differentiate the function with respect to x.

Answer:


u = (log x)x

Differentiating both sides with respect to x, we obtain



Differentiating both sides with respect to x, we obtain

Therefore, from (1), (2), and (3), we obtain

Question 8:
Differentiate the function with respect to x.

Answer:



Differentiating both sides with respect to x, we obtain

Therefore, from (1), (2), and (3), we obtain

Question 9:
Differentiate the function with respect to x.

Answer:


Differentiating both sides with respect to x, we obtain


Differentiating both sides with respect to x, we obtain

From (1), (2), and (3), we obtain

Question 10:
Differentiate the function with respect to x.

Answer:


Differentiating both sides with respect to x, we obtain


Differentiating both sides with respect to x, we obtain

From (1), (2), and (3), we obtain

Question 11:
Differentiate the function with respect to x.

Answer:


Differentiating both sides with respect to x, we obtain


Differentiating both sides with respect to x, we obtain

From (1), (2), and (3), we obtain

Question 12:
Find
of function.


Answer:
The given function is

Let xy = u and yx = v
Then, the function becomes u + v = 1


Differentiating both sides with respect to x, we obtain


Differentiating both sides with respect to x, we obtain

From (1), (2), and (3), we obtain

Question 13:
Find
of function.


Answer:
The given function is

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Question 14:
Find
of function.


Answer:
The given function is

Taking logarithm on both the sides, we obtain

Differentiating both sides, we obtain

Question 15:
Find
of function.


Answer:
The given function is

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Question 16:
Find the derivative of the function given by
and hence find
.


Answer:
The given relationship is

Taking logarithm on both the sides, we obtain

Differentiating both sides with respect to x, we obtain

Page No 179:
Question 18:
If u, v and w are functions of x, then show that

in two ways-first by repeated application of product rule, second by logarithmic differentiation.
Answer:
Let 

By applying product rule, we obtain

By taking logarithm on both sides of the equation
, we obtain


Differentiating both sides with respect to x, we obtain
