Question

Calculati sinusul ,cosinusul,tangenta :1)120. 2)135. 3)150.

Answer 1

Sin120°=sin(90°+30°)=cos30°=√3/2
или sin120°=sin(180°-60°)=sin60°=√3/2

cos120°=cos(90°+30°)=-sin30°=-1/2

tg120°=tg(90°+30°)=-ctg30°=-√3

2. sin135°=sin(90°+45°)=sin45°=√2/2
cos135°=cos(90°+45°)=-sin45°=-√2/2
tg135°=tg(90°+45°)=-ctg45°=-1
ctg135°=ctg(90°+45°)=-tg45°=-1

3. sin150°=sin(90°+60°)=sin60°=√3/2
cos150°=sin(180°-30°)=sin30°=1/2
tg150°=tg(90°+60°)=-ctg60°=-1/√3