# Math Help - Evaluating the definite integral

1. ## Evaluating the definite integral

2. Hi Diesel, it is preferred you post your attempts at each problem here at MHF.

I am prepared to give you a hand by showing you a similar problem

Consider the following integral $\int_{-1}^3(2x+5)~dx$

Applying the rule $\int x^n~dx = \frac{x^{n+1}}{n+1}+C$

We obtain $\int_{-1}^3(2x+5)~dx = \left[x^2+5x\right]_{-1}^3$

Now to find the definite integral's value we say $\left[3^2+5\times 3\right]-\left[{(-1)}^2+5\times (-1)\right]=\dots$

I'll let you take care of the arithmetic.

And here's a hint for the second question

$\frac{3}{x^4} = 3x^{-4}$

3. hey man thanks a lot, thats exactly the kind of answer i was looking for, i can't thank you enough. i will now do these types well on the Final!!