Question

Help please?

Answer 1

`d` is correct.

Explanation:

Rewrite in terms of cosine, using `secx =1/cosx` and `tanx= sinx/cosx`.

`=(3(1/cos^2theta - sin^2theta/cos^2theta))/(2/cos^3theta)`

Recall that `sin^2x+ cos^2x= 1`.

`= (3((1 - sin^2theta)/cos^2theta))/(2/cos^3theta)`

`= ((3cos^2theta)/cos^2theta)/(2/cos^3theta)`

`= 3/2cos^3theta`

The answer therefore is `d`.

Hopefully this helps!