Question

graphing sine and cosine functions
what is one characteristic of the cosine function?
it is an odd function.
its graph is symmetric about the y-axis.
its domain is between $-1$ and $1$ and is inclusive.
it has a period equal to $\pi$

Explanation:

• An odd function satisfies $f(-x) = -f(x)$; cosine satisfies $f(-x)=f(x)$, so it is even, not odd.
• The cosine function's graph is symmetric about the y-axis, which is a key property of even functions.
• The domain of cosine is all real numbers; its range is $[-1,1]$, not the domain.
• The period of cosine is $2\pi$, not $\pi$.

Answer:

Its graph is symmetric about the y-axis.