Question

use the trigonometric function values of quadrantal angles to evaluate the expression below.
( cos 360°)² - ( sin 270°)²

( cos 360°)² - ( sin 270°)² = □
(simplify your answer, including any radicals. use integers or fractions for any numbers in the expression.)

Explanation:

Step1: Find $\cos 360^\circ$

The angle $360^\circ$ is a quadrantal angle, and $\cos 360^\circ = \cos 0^\circ = 1$. So $(\cos 360^\circ)^2 = 1^2 = 1$.

Step2: Find $\sin 270^\circ$

The angle $270^\circ$ is a quadrantal angle, and $\sin 270^\circ = - 1$. So $(\sin 270^\circ)^2 = (-1)^2 = 1$.

Step3: Subtract the two results

Now we calculate $(\cos 360^\circ)^2 - (\sin 270^\circ)^2$: $1 - 1 = 0$.

Answer:

$0$