化简sin(60°+2x)*cos(60°-2x)

问题描述:

化简sin(60°+2x)*cos(60°-2x)

解:
原式=[√3/2cos(2x)+1/2sin(2x)][1/2cos(2x)+√3/2sin(2x)]
=√3/4cos^2(2x)+sin(2x)*cos(2x)+√3/4sin^2(2x)
=√3/4+1/2sin(4x)

sin(60°+2x)*cos(60°-2x)
=1/2(sin(60°+2x+60°-2x)+sin(60°+2x-(60°-2x))
=1/2(sin120°+sin4x)
=1/2(√3/2+sin4x)