I am having difficulties simplifying trigonometric expressions. My textbook isn't much help and I don't have a teacher to ask, so I thought maybe someone here could help me.

Some examples of questions I'm not really sure about are:

1) sinx / tanxcosx

The answer I got for this one simply "1".

2) sin(^4)x + (sin(^2)x)(cos(^2))

This one I got "sinx(^4)x + 1"

3)

sinx - (sinx)(cos(^2)x)

------------------------

sin(^2)x

I am lost on this one.

Any help would be greatly appreciated.