Question

sin( -145°)=

sin( -960°)=

ctg (-315°)=

Answer 1

sin( -145°)=-sin(90+55)=-cos55=-0.5736

sin( -960°)=-sin(3*360-120)=sin120=sin(90+30)=cos30=$frac{sqrt{3}}{2}$

ctg (-315°)=-ctg(270+45)=tg45=1