Question

If we know the values of the sine and cosine of x and y, we can find the value of cos(x - y) by using the ____ Formula for Cosine. State the formula: cos(x - y) = ____.

Answer 1

Answer:

$\cos(x - y) = \cos(x)\cos(y) + \sin(x)\sin(y)$

Step-by-step explanation:

Given

$\cos(x - y)$

Required

State the formula

From trigonometry identity, the formula of $\cos(x - y)$ is:

$\cos(x - y) = \cos(x)\cos(y) + \sin(x)\sin(y)$