S^3+2S^2+2S+3=0
问题描述:
S^3+2S^2+2S+3=0
答
令S=Cosx+iSinx
S0:
Cos3x+iSin3x+2Cos2x+iSin2x+2Cosx+iSinx+3=0
So:
cos3x+2cos2x+3=0
sin3x+2sin2x+sinx=0
化解可以解出答案,共有3个解