CPM Homework Help : PC Problem 7-24

The sine and cosine functions can be classified as even, odd, or neither. The diagrams below show why.

This shows that $\cos\left(−x\right) =$ ____ and $\sin\left(−x\right) =$ ____.
Answer (a):
$\cos\left(−x\right) = \cos\left(x\right)$ and $\sin\left(−x\right) = −\sin x$
Classify the $y = \sin x$ and $y = \cos x$ as either even or odd.
Answer (b):
Sine is odd, cosine is even.

Periodic curve labeled, y = cosine x, with 3 visible turning points, middle turning point at (0, comma 3), vertical segment from point on curve in third quadrant, labeled, f of negative x, to negative x axis, at point labeled, negative x, & vertical segment from point on curve in fourth quadrant, labeled, f of x, to positive x axis, at point labeled x, vertical segments are same length. Periodic curve labeled, y = sine x, with 4 visible turning points, passing through the origin, vertical segment from point on curve in third quadrant, labeled, f of negative x, to negative x axis, at point labeled, negative x, & vertical segment from point on curve in first quadrant, labeled, f of x, to positive x axis, at point labeled x, vertical segments are same length.