Double Angle help

[val1]

Please can you help me to solve the following equation for
\(\displaystyle 0^\circ \le x \le 360^\circ\)

\(\displaystyle \L
2\sin 2x \pm \cos x = 0\)

:?:

Thank you

 

[tkhunny]

That's not a valid equation. The +/- thing doesn't mean anything in this context.

Do you mean to solve BOTH

2* sin(x) + cos(x) = 0 and 2* sin(x) - cos(x) = 0

In any case, is probably will be helpful to know that sin(2x) = 2*sin(x)*cos(x)

 

[val1]

I think it meant to solve for both plus and minus cos (x)

I used the formula and got some solutions that seem ok.

Thank you