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## anonymous one year ago If sin theta=3/5 and theta is in quad 2 the exact form of cos (5pi/3-theta) is .....? I just need help with it I can do the work but a little help could help lol

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1. 0_0youscareme
2. anonymous

o.O thats not the same question

3. anonymous

Yeah I know for sure thats not the right answer lol

4. anonymous

Use the compound angle formula for cos,

5. 0_0youscareme

i put the link there bcuz that he just put copy and paste

6. anonymous

this thing is refusing to let me use the equation tool... cos(A-B)=cosAcosB+sinAsinB

7. 0_0youscareme

i never said it had the answer

8. anonymous

Nono lol I was talking about jacob

9. 0_0youscareme

yeah but i put the link were he copy and pasted the answer some1 else put

10. anonymous

I got the answer 3sqrt3-4/10 but thats the same answer as another problem I did

11. anonymous

he deleted it i think... XD

12. anonymous

$\sin \Theta=\frac{ 5 }{ 3 }$ $\cos \theta=\frac{ 4 }{ 5 }$ $\cos (\frac{ 5\pi }{ 3 }-\theta)=\cos \frac{ 5\pi }{ 3 } \cos \theta + \sin$

13. anonymous

oops incomplete... k im not used to this equation tool. meant to be sin5pi/3sin(theta)

14. anonymous

@zepdrix Do you have any idea of how this is done? I think my work is correct

15. anonymous

$=\frac{ 1 }{ 2 }\frac{ 4 }{ 5 }+(-\frac{ \sqrt{3} }{ 4 })\frac{ 3 }{ 5 }$

16. anonymous

I think I got it now after doing it

17. anonymous

But the way you were doing it was a little wrong lol

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