Thread: Solve Trig eqauions

Solve, finding all solutions in 0<x<=360

1. Sin4x-2sin2x=0

I know I'm going to need to use the double-angle and/or sum to product identities but i'm not sure how to proceed.

2. Sin2xCosx+Sinx=0

similar to above. Can anyone help me please?

Originally Posted by Tmiles

Solve, finding all solutions in 0<x<=360

1. Sin4x-2sin2x=0

I know I'm going to need to use the double-angle and/or sum to product identities but i'm not sure how to proceed.

2. Sin2xCosx+Sinx=0

similar to above. Can anyone help me please?

In each case, substitute sin(2x) = 2 sin(x) cos(x) and factorise by taking out a common factor of sin(x). Then use the null factor law etc.