# Find the derivative of the function using the definition of the derivative. g(x) = 4 − x.

We will use the concept of first principle differentiation to find the derivative.

## Answer: Derivative of the function using the definition of the derivative is -1.

Let us see how we will use the concept of first principle differentiation to find the derivative.

**Explanation**:

Given: g(x) = 4 − x.

The differentiation by the first principle states that,

f^{'}(x) = [f (x + h) - f(x)] / h where h << 0

Thus, in terms of g(x) we will have

g'(x) = [g (x + h) - g(x)] / h where h << 0

Hence on substituting the values we get,

g'(x) = [4 - (x + h) - 4 + x] / h

g'(x) = - h / h = -1