# Negative area between two curves

1. Dec 9, 2013

I've been trying to figure out what a negative area means, but I can't.

The problem statement, all variables and given/known data
Calculate the area between $f(x) = 3^{x} \, , \, g(x)=2x+1$

The attempt to a solution
The intersections are located in $x=0$ and $x=1$.
So I do the integral from 0 to 1.
$\int_{0}^{1} (g(x)-f(x))dx = \frac{2}{log(3)}-2 \approx -0.17952154675$

What am I doing wrong? I am integrating the upper function minus the lower function.

2. Dec 9, 2013

### ShayanJ

The Negative is only telling that the function $3^x-2x-1$,has negative values more than positive ones inside the interval of integration and of course by integrating $2x+1-3^x$ you will get a positive answer!It is obvious from this that the sign doesn't mean much.

3. Dec 9, 2013

### MrAnchovy

No, you have swapped f(x) and g(x) in this step.