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