Question

Out of the following choices, what is the derivative of -sec(x)(x^2+tan(x)) (There's an attachment)

Answer 1

It is c, for sure.

Answer 2

There is two tricks,
\[1+\tan^2x=\frac{1}{\cos^2x}\]And put all sin^2 of the final expression as cos^2 using,
\[1-\sin^2x=\cos^2x\]

Answer 3

Lovely, thanks again!!!