Question

Value after differentiating cos (x^2+5) is ________

(a) 5.sin (x^2+5)

(b) -sin (x^2+5).2x

(c) sin (x^2+5).2x

(d) cos (x^2+5).2x

I had been asked this question during a job interview.

I'm obligated to ask this question of Differentiability topic in section Continuity and Differentiability of Mathematics – Class 12

Answer 1

Correct option is (b) -sin (x^2+5).2x

For explanation I would say: We differentiate the given function with help of chain rule and hence the outer function becomes –sin and the inner function is differentiated into 2x, therefore the answer comes out to be -sin (x^2+5).2x.