Hello, SodaCup!

We have: .Given the equation: . , find

I've tried using: .

but I don't know what to do next.

How about combining the -1 and -3?

Factor: .

And we have two equations to solve:

. .

. .

Therefore: .

We can use two identities: .Evaluate: .

So that: .

Then: .

Note that: .