# Thread: Urgent!! Need help with this trigonometric question

2. ## Re: Urgent!! Need help with this trigonometric question

What is the question? You have an expression, followed by a given equation that does not seem to have any bearing on the expression. Are you supposed to simplify?

3. ## Re: Urgent!! Need help with this trigonometric question

Originally Posted by xytfaith
I suppose you are to simplify this?

$\displaystyle sin(x + y) = sin(x) cos(y) + sin(y) cos(x)$
$\displaystyle cos(x + y) = cos(x) cos(y) - sin(x) sin(y)$