(v) sin 3x + cos2x = 0
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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
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