What is the derivative of y=sec(x) tan(x)y=sec(x)tan(x)?

1 Answer
Sep 11, 2014

By Product Rule, we can find
y'=secx(1+2tan^2x)y'=secx(1+2tan2x).

Let us look at some details.
y=secxtanx

By Product Rule,
y'=secxtanx cdot tanx+secx cdot sec^2x

by factoring out sec x,
=secx(tan^2x+sec^2x)

by sec^2x=1+tan^2x,
=secx(1+2tan^2x)