Řešení - Trigonometry

The period of trigonometric functions is 360 degrees.

$$\sin \left(690°\right)=\sin \left(690-360°\right)$$

Subtracting one integer from another.

$$\sin \left(690-360°\right)=\sin \left(330°\right)$$

Reflecting the number with respect to 360 degrees.

$$\sin \left(330°\right)=\sin \left(360-30°\right)$$

The period of trigonometric functions is 360 degrees.

$$\sin \left(360-30°\right)=\sin \left(360-30-360°\right)$$

Removing or simplifying the same numbers on the top and bottom of a fraction.

$$\sin \left(360-30-360°\right)=\sin \left(-30°\right)$$

Computing the sine of a negative angle.

$$\sin \left(-30°\right)=-\sin \left(30°\right)$$

Computing the sine of 30 degrees.

$$-\sin \left(30°\right)=-\frac{1}{2}$$