NCERT Class XI Mathematics - Limits and Derivatives - Solutions

Question : 68

Total: 72

(x + cos x)(x – tan x)

Solution:

Let f(x) = (x + cos x) (x – tan x) ... (i)
Differentiating (i) with respect to x, we get

[f (x)] = (x + cos x)′ (x − tan x)+ (x − tan x)′ (x + cosx)
= (1 – sin x) (x – tan x) + (1 – sec2 x) (x + cos x)
= (1 – sin x) (x – tan x) + (– tan2 x) (x + cos x)

Go to Question:

Prev Question

Next Question