计算,sin(π/12)-sin(5π/12)+2sin(π/8)sin(3π/8)
问题描述:
计算,sin(π/12)-sin(5π/12)+2sin(π/8)sin(3π/8)
答
sin(π/12)-sin(5π/12)+2sin(π/8)sin(3π/8)
=sin(π/12)-cos(π/12)+2sin(π/8)cos(π/8)
=√2sin(π/12-π/4)+sin(π/4)
=-√2sin(π/6)+sin(π/4)
=-√2/2+√2/2
=0