Calculate the derivative of f(x)=2x^2+4 by using the defn of the derivative.

Question

I keep getting the wrong answer?

Calculate the derivative of f(x)=2x^2+4 by using the defn of the derivative.

I keep getting 2x and I know this is incorrect! Not sure what I am doing wrong.

Answer 1

Step 1 :

Definition :

The derivative of a function f  with respect to x  is denoted by .

  if this limit exists.

Step 2 :

The function is .

Find :

The derivative of a function.

Substitute the limit.

Solution :