Thread: Please help me (solve trigonometry equation)

Code:

Find all solutions of
2 cos(3x)^2 + sin(3x)

I can simplify it all the way down to cos(6x) + sin(3x) = 0, however I get stuck here

Originally Posted by Ccrow

Code:

Find all solutions of
2 cos(3x)^2 + sin(3x)

I can simplify it all the way down to cos(6x) + sin(3x) = 0, however I get stuck here

I don't believe your expression is correct. Try it this way:


So


So your equation becomes:




which you can treat as a standard quadratic.

-Dan

Hello, Ccrow!

I'll take a guess at what you meant . . .

Find all solutions of: .

Replace with

. . then: .

And we have the quadratic: .

Quadratic Formula: .

We must discard the positive square root: .


So we have: .

Therefore: .

Soroban you can have but you will be required to use complex numbers. I assume that he only wanted the real solutions any way, but just thought id point that out.