求下列各三角函数的值,(1)cos(-1050度)(2)sin(-31/4π)
问题描述:
求下列各三角函数的值,(1)cos(-1050度)(2)sin(-31/4π)
答
cos(-1050度)
=cos30°
=√3/2
sin(-31/4π)
=sin(π/4)
=√2/2
答
cos(-1050)=cos(-1080+30)=cos(-360*3+30)=cos30=根号3/2
sin(-31/4Pai)=sin(-8Pai+Pai/4)=sinPai/4=根号2/2