Question

Question #8842f

Answer 1

All you need to do is plug `5` into the derivative.

`f'(x)=-sinx-4sec^2x`

`f'(5)=-sin(5)-4sec^2(5)`

You can plug this straight into something like Wolfram Alpha.

On a calculator, depending on what type you have, you may not have the `sec` button and instead have to use `cos`:

`f'(5)=-sin(5)-4/(cos(5))^2`

I also assume you're working with radians. Without knowing how many digits you need, you should get:

`f'(5)=-48.75260255517...`