# What is the integral of #(x^2 - 4)dx# from 0 to 4?

##### 1 Answer

The answer for

When it comes to integrals, probably the best way is to think to yourself, "If I solved for an anti-derivative or integral, does taking the derivative of my answer give me the original function in the problem?"

To solve this integral, what you can do is split it up as follows:

(1)

To integrate *polynomials*;

(2)

C denotes some constant that is **crucial** when doing *indefinite* integrals for all functions! By doing

This makes sense since taking the derivative of

If I take the definite integral of it however, I won't need the C since they would cancel. In addition, I need to evaluate from

(3)

Thus, keep in mind that the constant *sometimes* a zeroth term in the integral can be ignored while evaluating (unlike

For

And then we can solve for the sum of

(4)

So now, we can combine Equations 3 and 4 to get the answer to Eq. 1:

You can also just stick with the original function and integrate the sums inside knowing that they are separate, but the procedures above is a good way for beginners on definite integrals.

Remember that on some functions, they behave differently than polynomials, so just be aware of the derivatives.