Thread: 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.

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

Originally Posted by homeylova223

sinxtanx-sinx=0

sin(x) tan(x) - sin(x) = 0

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

etc.

-Dan

You are really skilled in math.

Originally Posted by homeylova223

You are really skilled in math.

No really. I'm blushing...

-Dan