cos3x * sin5x/ cos5x = sin7x
cos3x.sin5x = sin7x.cos5x
sin 8x+ sin2x = sin12x+sin2x ( sinx cosy = (sinx+siny)+(sinx-siny) 忘记这个定理名字叫什么了)
sin8x = sin12x
x=frac{kpi}{2}
x=frac{pi}{20}+frac{kpi}{10}
k is constant ,可以是任何数.
cos3x * sin5x/ cos5x = sin7x
cos3x.sin5x = sin7x.cos5x
sin 8x+ sin2x = sin12x+sin2x ( sinx cosy = (sinx+siny)+(sinx-siny) 忘记这个定理名字叫什么了)
sin8x = sin12x
x=frac{kpi}{2}
x=frac{pi}{20}+frac{kpi}{10}
k is constant ,可以是任何数.