Solve the equation sin x + sin 2x = 0 , for 0°< x < 360°?

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Answer 1 · 2018-05-10T23:47:09

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#sinx+sin2x=0#

#sinx+[2*sinx*cosx]=0#

#sinx[1+2cosx]=0#

#sinx=0#

#x=0,x=2pi or x=pi#

#1+2cosx=0#

#2cosx=-1#

#cosx=-1/2#

#x=(2pi)/3 or x=(4pi)/3#

note that

#sin2x=2*sinx*cosx#