คำตอบ - Trigonometry

Reflecting the number with respect to 360 degrees.

$$\cot \left(157°\right)=\cot \left(180-23°\right)$$

The cotangent of an angle is equal to the cosine of the angle divided by the sine of the angle.

$$\cot \left(180-23°\right)=\frac{\cos \left(180-23°\right)}{\sin \left(180-23°\right)}$$

Reflecting the cosine function with respect to 180 degrees.

$$\frac{\cos \left(180-23°\right)}{\sin \left(180-23°\right)}=\frac{-\cos \left(23°\right)}{\sin \left(180-23°\right)}$$

Reflecting the sine function with respect to 180 degrees.

$$\frac{-\cos \left(23°\right)}{\sin \left(180-23°\right)}=\frac{-\cos \left(23°\right)}{\sin \left(23°\right)}$$

Placing the minus sign in front of a fraction.

$$\frac{-\cos \left(23°\right)}{\sin \left(23°\right)}=-\frac{\cos \left(23°\right)}{\sin \left(23°\right)}$$

The cotangent of an angle is equal to the cosine of the angle divided by the sine of the angle.

$$-\frac{\cos \left(23°\right)}{\sin \left(23°\right)}=-\cot \left(23°\right)$$