# Question #0d7b8

##### 2 Answers

i) see below

ii) In the graph of an even function the left side relative to the Y-axis is a reflection of the right side (relative to the Y-axis),

#### Explanation:

i) using the identity:

ii) Note that the reflection of the right side of

Therefore

and

When x is expressed in radian, the Maclaurin series for cos x and sin

x are

,

It follows that

If

So, sine is even and cosine is odd.

For even functions y = f(x), like cos x,

if (x, y) is on the graph, then (-x, y) is on

it. So, the graph is symmetrical about the y-axis.

For odd f like sin x,

if (x, y) is on the graph, so is (x, -y). And so, the graph is

symmetrical about x-axis.