Question

How do i work out sinx+2sinxcosx=0 in radians?

Answer 1

First factor out a sin(x)

`sin x (1 + 2cos x) = 0`
Now you can split it into factors, where each factor = 0 and solve them separately.

`sin x = 0 , 1 + 2cos x = 0`

`sin x = 0 , cos x = -(1)/(2)`
You can use the unit circle to find the appropriate angles:(attached)
sin x = 0 when

`x = 0, \pi`
cos x = -1/2 when

`x = (2 \pi )/(3), (4 \pi )/(3)`