f(x)=(1+sinx+cosx)[sin(x/2)-cos(x/2)]/根号(2+2cosx)

问题描述:

f(x)=(1+sinx+cosx)[sin(x/2)-cos(x/2)]/根号(2+2cosx)
(1)f(x)的化简形式(最好有过程)

f(x)=(1+sinx+cosx)[sin(x/2)-cos(x/2)]/√(2+2cosx)
=[sin²(x/2)+cos²(x/2)+sinx+cosx][sin(x/2)-cos(x/2)]/[√2(1+cosx)]
=[sin²(x/2)+cos²(x/2)+2sin(x/2)*cos(x/2)+cos²(x/2)-sin²(x/2)][sin(x/2)-cos(x/2)]/[√4*(1+cosx)/2]
={[sin(x/2)+cos(x/2)]²+[cos(x/2)+sin(x/2)][cos(x/2)-sin(x/2)]}[sin(x/2)-cos(x/2)]/[√4*cos²(x/2)]
={[sin(x/2)+cos(x/2)][sin(x/2)+cos(x/2)+cos(x/2)-sin(x/2)]}[sin(x/2)-cos(x/2)]/[√4*cos²(x/2)]
={[sin(x/2)+cos(x/2)]*2cos(x/2)}[sin(x/2)-cos(x/2)]/[2*cos(x/2)]
={[sin(x/2)+cos(x/2)][sin(x/2)-cos(x/2)]*2cos(x/2)}/[2*cos(x/2)]
=[sin(x/2)+cos(x/2)][sin(x/2)-cos(x/2)]
=sin²(x/2)-cos²(x/2)
不明白的地方M我