Hello Chicken Enchilada

Welcome to Math Help Forum.

You've come to the right place!To solve problems involving inverse trig functions, like , let (or some variable) equal the inverse function and then express it the other way round; that is, in terms of the original trig function. So here:

Let and .

Then and , and we want to find

Now expand:

We know and . So all that remains is to find and , which we can do using Pythagoras' Theorem (or , which is essentially the same thing).

So, (Can you see why?)

and ?

So ?

Can you complete it now?

(And for the second one, use )

Grandad