Réitigh sin(7pi/4)

$$\sin ( \frac { 7 \pi } { 4 } )$$

Luacháil

$$-\frac{\sqrt{2}}{2}\approx -0.707106781$$

Céimeanna Réitigh

Bain úsáid as \sin(x+y)=\sin(x)\cos(y)+\sin(y)\cos(x) nuair atá x=\frac{3\pi }{2} agus y=\frac{\pi }{4}ann chun an toradh a fháil.

$$\sin(\frac{3\pi }{2}+\frac{\pi }{4})=\sin(\frac{3\pi }{2})\cos(\frac{\pi }{4})+\sin(\frac{\pi }{4})\cos(\frac{3\pi }{2})$$

Faigh luach do\sin(\frac{3\pi }{2})ón dtábla luachanna triantánúla.

$$-\cos(\frac{\pi }{4})+\sin(\frac{\pi }{4})\cos(\frac{3\pi }{2})$$

Faigh luach do\cos(\frac{\pi }{4})ón dtábla luachanna triantánúla.

$$-\frac{\sqrt{2}}{2}+\sin(\frac{\pi }{4})\cos(\frac{3\pi }{2})$$

Faigh luach do\sin(\frac{\pi }{4})ón dtábla luachanna triantánúla.

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

Faigh luach do\cos(\frac{3\pi }{2})ón dtábla luachanna triantánúla.

$$-\frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2}\times 0$$

Déan áirimh.

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