คำตอบ - Trigonometry

The cosecant of an angle is equal to one divided by the sine of the angle.

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

Computing the sine of 30 degrees.

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

Computing the reciprocal of a reciprocal.

$$\frac{1}{\frac{1}{2}}=2$$