Question

Reflecting the graph of y=cosx across the y axis is the same as not reflecting it at all.
True or False

Answer 1

Refrecting the graph of y = cos x across the y axis is the same as not refrecting it at all since y = cos x is an even function. i.e. cos x = cos (-x). Hence the statement is true.

Answer 2

Answer:

True

Step-by-step explanation:

The graph of $y=\cos(x)$ is an even function.

This means that the graph of $y=\cos(x)$ is symmetric about the y-axis.

If we reflect the graph of $y=\cos(x)$ about the y-axis, it will fall exactly on its outline.

This makes it behave as if it has not been reflected at all.

In other words, the mapping for reflection about the y-axis is

$(x,y)\rightarrow(-x,y)$

Since $\cos(-x)=\cos(x)$

The graph will retrace its outline.