

NCERT Solutions for Class 12 Maths Chapter 5 Miscellaneous Exercise
Solve The Following Questions NCERT Solutions For Class 12 Maths Chapter 5 Exercise 5.5 Continuity and Differentiability
Question 1. Differentiate the function with respect to x.cos x.cos 2x.cos3x
Solution : Let y = cos x.cos 2x.cos3x Taking logarithm on both the sides, we obtain
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.1
Question 2. Differentiate the function with respect to x.
Solution :
Let y =
Taking logarithm on both the sides, we obtain
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.2
Question 3. Differentiate the function with respect to x.
Solution :
Let, y =
Taking logarithm on both the sides, we obtain
log y = cos x .log(log x)
Differentiating both sides with respect to x, we obtain
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.3
Question 4. Differentiate the function with respect to x.
Solution :
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.4
Question 5. Differentiate the function with respect to x.
Solution :
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.6
Question 6. Differentiate the function with respect to x.
Solution :
Differentiating both sides with respect to x, we obtain
Differentiating both sides with respect to x, we obtain
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.7
Question 7. Differentiate the function with respect to x.
Solution :
Differentiating both sides with respect to x, we obtain
Differentiating both sides with respect to x, we obtain
NCERT Solutions for Class 12 Maths Chapter 5 Exercise 5.8
Question 8. Differentiate the function with respect to x.
Solution :
Differentiating both sides with respect to x, we obtain
Question
9. Differentiate the function with respect to x.
Solution :
Let, y =
Differentiating both sides with respect to x, we obtain
Differentiating both sides with respect to x, we obtain
Question
10. Differentiate the function with respect to x.
Solution :
Let, y =
Differentiating both sides with respect to x, we obtain
Differentiating both sides with respect to x, we obtain
Question
11. Differentiate the function with respect to x.
Solution :
Let, y =
Differentiating both sides with respect to x, we obtain
Differentiating both sides with respect to x, we obtain
Question
12. Find dy/dx of function.
x
y
+ y
x
= 1
Solution :
The given function is x
y
+ y
x
= 1
Let x
y
= u and y
x
= v
Then, the function becomes u + v = 1
∴du/dx + dv/dx = 1
Differentiating both sides with respect to x, we obtain
Differentiating both sides with respect to x, we obtain
Question
13. Find dy/dx of function.
y
x
= x
y
Solution :
The given function is y
x
= x
y
Taking logarithm on both the sides, we obtain
x log y = y log x
Differentiating both sides with respect to x, we obtain
Question
14. Find dy/dx of function.
(cos x) y = (cos y) x
Solution : The given function is (cos x) y = (cos y) x Taking logarithm on both the sides, we obtain y log cos x = x log cos y Differentiating both sides, we obtain
Question
15. Find dy/dx of function.
xy = e (x-y)
Solution : The given function is xy = e (x-y) Taking logarithm on both the sides, we obtain log(xy) = log(e (x-y) ) Differentiating both sides with respect to x, we obtain
Question
16. Find the derivative of the function given by
and hence find f'(1)
Solution :
The given relationship is
Taking logarithm on both the sides, we obtain
Differentiating both sides with respect to x, we obtain
Question
17. Differentiate
in three ways mentioned below
(i) By using product rule.
(ii) By expanding the product to obtain a single polynomial.
(iii By logarithmic differentiation.
Do they all give the same answer?
Solution :
Let, y =
(i)
(ii)
(iii) y =
Taking logarithm on both the sides, we obtain
Differentiating both sides with respect to x, we obtain
From the above three observations, it can be concluded that all the results of dy/dx are same.
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.
Solution :
Let y = u.v.w = u(v.w)
By applying product rule, we obtain
By taking logarithm on both sides of the equation y = u.v.w, we obtain
log y = log u + log v + log w
Differentiating both sides with respect to x, we obtain
