已知sin(x+π )=—1/2,计算:sin(5π —x)—cos(x—3π /2)

问题描述:

已知sin(x+π )=—1/2,计算:sin(5π —x)—cos(x—3π /2)

sin(x+π )=—1/2 得sinx=1/2 得sin(5π —x)—cos(x—3π /2) =sinx+sinx=2sinx=1