# Thread: Trig Identity math question.

1. ## Trig Identity math question.

In TrianglePQR:

3sinP + 4 CosQ= 6
and
SinQ +3 CosP= 1

a)find Sin(P+Q)
b)Determine the measure of angle R in radians.

If any one can help me solve this, I would really appreaciate it!

2. Have you seen this?

$a \sin x + b \cos x= \sqrt{a^2+b^2}\sin(x+\psi) , \psi = \arctan\left(\frac{a}{b}\right)$

3. No I haven't.

4. Now you have, try to apply it to your problem.

5. Ok, I will give it a shot.

6. Sorry for the double post, what would I use for Y.

7. Using a and b

Originally Posted by pickslides
Have you seen this?

$\psi = \arctan\left(\frac{a}{b}\right)$

8. Ok thanks! I really need this problem solved. Hopefully this works out!

9. I still cant work it out!