# Problem Solving this equation!

Hi I was wondering if anybody could help solve this equation. I have the answer but i cant seem to work out how my teacher arrived at this,

Many thanks
Alex

alpha
A = constant

## Homework Equations

Solve for [sin(alpha)]^2

A^2- [sin(alpha)]^2*(A^2+2)+2*[sin(alpha)]^4

## The Attempt at a Solution

The solution is given as

[sin(alpha)]^2 = (A^2)/2 or 1

tiny-tim
Homework Helper
Welcome to PF!

Hi Alex! Welcome to PF! (try using the X2 tag just above the Reply box )

So you mean solve A2 - B(A2 + 2) + 2B2 = 0 for B?

Hi,

Yes that the question. I realise that it is basically a simple quadratic but when i try to solve it using to the quadratic formula I don't end up with the required results?

Thanks again

Alex

berkeman
Mentor
Hi,

Yes that the question. I realise that it is basically a simple quadratic but when i try to solve it using to the quadratic formula I don't end up with the required results?

Thanks again

Alex

Please post your work, so we can see where you are going wrong...

Hi,

I've just manage to solve it! Thanks for your offers of help, very kind.

Merry Christmas

Alex