Datrys cos(7pi/6)

$$\cos ( \frac{ 7 \pi }{ 6 } )$$

Enrhifo

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

Camau Ateb

Defnyddio \cos(x+y)=\cos(x)\cos(y)-\sin(y)\sin(x) lle mae x=\pi a y=\frac{\pi }{6} i gael y canlyniad.

$$\cos(\pi +\frac{\pi }{6})=\cos(\pi )\cos(\frac{\pi }{6})-\sin(\frac{\pi }{6})\sin(\pi )$$

Cael gwerth \cos(\pi ) o’r tabl gwerthoedd trigonometrig.

$$-\cos(\frac{\pi }{6})-\sin(\frac{\pi }{6})\sin(\pi )$$

Cael gwerth \cos(\frac{\pi }{6}) o’r tabl gwerthoedd trigonometrig.

$$-\frac{\sqrt{3}}{2}-\sin(\frac{\pi }{6})\sin(\pi )$$

Cael gwerth \sin(\frac{\pi }{6}) o’r tabl gwerthoedd trigonometrig.

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

Cael gwerth \sin(\pi ) o’r tabl gwerthoedd trigonometrig.

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

Gwnewch y gwaith cyfrifo.

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