Question

(v) sin 3x + cos2x = 0​

Answer 1

Answer:

sin(2x+x)=sin2x.cosx+cos2x.sinx

sin2x=2sinx.cosx

cos2x=2cosx^2-1

2sinx.cosx^2+(2cos^2x-1)sinx=0

2sinx.cosx^2+2cosx^2.sinx-sinx=0

4sinx.cosx^2-sinx=0

simx(4cosx^2-1)=0

4cosx^2=1

cosx^2=1/4

cosx=+-1/2

x=45degree or 225 degree