How to Find the Average Value of a Function Over a Given Interval?

KingKai
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Homework Statement



Determine the average value of the following function over the interval [0,6]

f(t) = (t2-1)e-0.5t

Homework Equations



1/(b-a) ∫ f(x) = {f(x)}

The Attempt at a Solution



Substitution?

let u = (t2-1)

du/dt = 2t

du/2t = dt

1/(6) ∫ u e-0.5t (du/2t)And here, I reach a roadblock.
 
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so to get the average of the function you integrate the function and then divide by the interval length.
 
Try a different technique.
 
KingKai said:

Homework Statement



Determine the average value of the following function over the interval [0,6]

f(t) = (t2-1)e-0.5t

Homework Equations



1/(b-a) ∫ f(x) = {f(x)}

The Attempt at a Solution



Substitution?

let u = (t2-1)

du/dt = 2t

du/2t = dt

1/(6) ∫ u e-0.5t (du/2t)

And here, I reach a roadblock.
Use integration by parts, twice.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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