证 sin2x * cos3x =(1/2) * [sin5x + sin(-x)]

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/25 01:52:37
证sin2x*cos3x=(1/2)*[sin5x+sin(-x)]证sin2x*cos3x=(1/2)*[sin5x+sin(-x)]证sin2x*cos3x=(1/2)*[sin5x+sin(-x

证 sin2x * cos3x =(1/2) * [sin5x + sin(-x)]
证 sin2x * cos3x =(1/2) * [sin5x + sin(-x)]

证 sin2x * cos3x =(1/2) * [sin5x + sin(-x)]
利用三角公式sin(a+b)+sin(a-b)=2*sin(a)cos(b),令a=2x,b=3x,则sin(5x)+sin(-x) = 2sin(2x)cos(3x),即sin(2x)cos(3x)=1/2*[sin(5x)+sin(-x)].