## hawkfalcon Group Title Find cos(theta) if tan(theta) = (-2/3) and sin(theta) > 0 2 years ago 2 years ago

1. hawkfalcon

Find $\cos \theta if \tan \theta = -2/3 and \sin \theta >0$

2. qpHalcy0n

Here, you know that the tangent is opp/adjacent. Since the sine is positive, it must be in either the first or second quadrant right?

3. hawkfalcon

Yes.

4. qpHalcy0n

So the opposite leg must be positive, therefore since the tangent is negative the adjacent leg must be the negative one. So what quadrant is that?

5. hawkfalcon

Oh so you know o and a, you just need to find the h, and you can solve it :P

6. qpHalcy0n

Yep.

7. qpHalcy0n

Lets see what ya got when ya get it.

8. hawkfalcon

9. hawkfalcon

Okay:)

10. qpHalcy0n

Yep.

11. hawkfalcon

$\frac{ -3 }{ \sqrt{13}}$

12. qpHalcy0n

Thats it.

13. hawkfalcon

:D thank you!

14. qpHalcy0n

No prob.

15. Yasir_se

$\frac{ x \sqrt{\left| x ^{2}-4 \right|} }{ x ^{2}-4 }-1>0$

16. hawkfalcon

@Yasir_se wtf?