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)

cos(-1050度)
=cos30°
=√3/2

sin(-31/4π)
=sin(π/4)
=√2/2

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