Question

cos(-70°6′)

将下列三角函数转化为锐角三角函数
cos13/9π=?
sin(1+π)=?
sin(-π/5)=?
cos(-70°6′)=?

Answer 1

cos13/9π=cos(π+4/9π)=-cos4/9π
sin(1+π)=-sin1
sin(-π/5)=-sin(π/5)
cos(-70°6′)=cos70°6′