Perhatikan gambar berikut
Jika OP=3OP=3OP=3 cm dan PQ=5PQ=5PQ=5 cm, maka cos(π+α)=....\cos\left(\pi+\alpha\right)=....cos(π+α)=....
−12-\frac{1}{2}−21
−718-\frac{7}{18}−187
718\frac{7}{18}187
222
12\frac{1}{2}21