4. Graphing Trigonometric Functions

For the topic of graphs of the sine and cosine functions, what is the axis of symmetry for the graph of $y=\left|x\right|$?

Given the graphs of $y=\sin \left(x\right)$ and $y=\cos \left(x\right)$, which of the following points lies on the y-axis and is also on the line that passes through the point $(0,1)$ and is parallel to the line passing through points $(0,0)$ and $(\pi ,0)$?

Graph each function over a two-period interval.

y = cos (x - π/2 )