Issolvi cos(5pidiv6)

$$\cos ( 5 \pi \div 6 )$$

Evalwa

$$-\frac{\sqrt{3}}{2}\approx -0.866025404$$

Passi tas-Soluzzjonijiet

Uża \cos(x+y)=\cos(x)\cos(y)-\sin(y)\sin(x) fejn x=\frac{\pi }{2} u y=\frac{\pi }{3} biex tikseb ir-riżultat.

$$\cos(\frac{\pi }{2}+\frac{\pi }{3})=\cos(\frac{\pi }{2})\cos(\frac{\pi }{3})-\sin(\frac{\pi }{3})\sin(\frac{\pi }{2})$$

Ikseb il-valur ta’ \cos(\frac{\pi }{2}) mit-tabella tal-valuri trigonometriċi.

$$0\cos(\frac{\pi }{3})-\sin(\frac{\pi }{3})\sin(\frac{\pi }{2})$$

Ikseb il-valur ta’ \cos(\frac{\pi }{3}) mit-tabella tal-valuri trigonometriċi.

$$0\times \frac{1}{2}-\sin(\frac{\pi }{3})\sin(\frac{\pi }{2})$$

Ikseb il-valur ta’ \sin(\frac{\pi }{3}) mit-tabella tal-valuri trigonometriċi.

$$0\times \frac{1}{2}-\frac{\sqrt{3}}{2}\sin(\frac{\pi }{2})$$

Ikseb il-valur ta’ \sin(\frac{\pi }{2}) mit-tabella tal-valuri trigonometriċi.

$$0\times \frac{1}{2}-\frac{\sqrt{3}}{2}\times 1$$

Agħmel il-kalkoli.

$$-\frac{\sqrt{3}}{2}$$