# Math Help - Trig equation

1. ## Trig equation

Solve (-2pi , 2pi)

what trig identities do you use?

2. Originally Posted by VkL
Solve (-2pi , 2pi)

what trig identities do you use?
most important one you need to use ...

$\cos^2(u) + \sin^2(u) = 1$

3. and what do you do with the tangent?

4. Originally Posted by VkL
and what do you do with the tangent?
$\tan\left(\frac{x}{2}\right) = 1$

you solve the equation.

5. Oh, Ok I see, How you got that.

But I still cannot solve it?

I got it down to sin(x/2)-Cos(x/2) = 0

6. Originally Posted by VkL
Oh, Ok I see, How you got that.

But I still cannot solve it?

I got it down to sin(x/2)-Cos(x/2) = 0
... where does $\sin\left(\frac{x}{2}\right) = \cos\left(\frac{x}{2}\right)$ in the given interval?

7. Pi/2 ??

8. Originally Posted by VkL
Pi/2 ??
that's one of the solutions in the interval ...

there is another.