Question

What is the Derivative of `y=x sec(kx)`?

Answer 1

By Product Rule,

`y'=1cdot sec(kx)+x cdot[sec(kx)]'`

by Chain Rule,

`=sec(kx)+x cdot [sec(kx)tan(kx)cdot k]`

by factoring out `sec(kx)`,

`=sec(kx)[1+kxtan(kx)]`