Question

Find \(\frac{dy}{dx}\) of y = sin (ax + b).

(a) a.cos (ax + b)

(b) b.sin (ax + b)

(c) a.sin (ax + b)

(d) a.cos (ax + b)

I got this question during a job interview.

My enquiry is from Differentiability in chapter Continuity and Differentiability of Mathematics – Class 12

Answer 1

Right answer is (a) a.cos (ax + b)

The explanation is: We differentiate the given function with the help of chain rule and hence

the outer function is differentiated into cos, and the inner function comes out to be a and the constant b becomes 0, which is multiplied to the whole function and the answer comes out to be

=> a.cos (ax + b).