# Math Help - Solving trigonometric equations?

1. ## Solving trigonometric equations?

Can anyone show me how to solve these two equations
sin2x=-sinx between 0 and 360 degrees

also

sinxtanx-sinx=0

I am not sure how do these.

2. Originally Posted by homeylova223
Can anyone show me how to solve these two equations
sin2x=-sinx between 0 and 360 degrees
Note that sin(2x) = 2 sin(x) cos(x), so
2 sin(x) cos(x) = -sin(x)

2 sin(x) cos(x) + sin(x) = 0

sin(x) [2 cos(x) + 1] = 0

Can you take it from there?

-Dan

3. Originally Posted by homeylova223
sinxtanx-sinx=0
sin(x) tan(x) - sin(x) = 0

sin(x) [ tan(x) - 1 ] = 0

etc.

-Dan

4. You are really skilled in math.

5. Originally Posted by homeylova223
You are really skilled in math.
No really. I'm blushing...

-Dan