# Is cos x even or odd?

Trigonometry is the branch of maths that deals with relationships between sides and angles of various geometrical objects.

## Answer: Cos x is an even function.

Let's understand the solution in detail.

**Explanation:**

To check for odd function, we need to verify if f(-x) = -f(x), and to check for even functions we check if it follows the relation f(-x) = f(x).

now, we check this for cos x:

⇒ f(x) = cos x

Since cos x is positive on the first and the fourth quadrant and -x is the angle taken from the x-axis in a clockwise direction, hence lying in the fourth quadrant.

⇒ f(-x) = cos (-x) = cos x

Hence, we see that f(-x) = f(x).