hawkfalcon 4 years ago Find cos(theta) if tan(theta) = (-2/3) and sin(theta) > 0

1. hawkfalcon

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

2. anonymous

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. anonymous

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. anonymous

Yep.

7. anonymous

Lets see what ya got when ya get it.

8. hawkfalcon

9. hawkfalcon

Okay:)

10. anonymous

Yep.

11. hawkfalcon

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

12. anonymous

Thats it.

13. hawkfalcon

:D thank you!

14. anonymous

No prob.

15. anonymous

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

16. hawkfalcon

@Yasir_se wtf?