Math Is Fun Forum

xXxEmZyxXx

Member

Registered: 2007-10-15

Posts: 12

new integration variable

Hey im trying to understand my lecture notes, i have the following method of integration which is confusing me

here the new integration variable delta is used as

so we have

this i understand but then my notes say

which is where i get confused. does anyone know how to calculate this x-1?? any help would be much appreciated

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: new integration variable

Hi xXxEmZyxXx;

You didn't remember your own notes, happened to me more than once:

Start here:

Add 1 to both sides:

combine the LHS:

This is the toughest step: Factor the numerator, takes some trial and error and some stubborness.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

xXxEmZyxXx

Member

Registered: 2007-10-15

Posts: 12

Re: new integration variable

ahh i understand that now must have missed a step.
suppose i want to change the denominator to

im assuming i use the same method though using a different integration variable delta as

now i've tried doing it like this and it gets a bit messy and im finding it hard to calculate the dx's does anyone have a suggestion for a different integration variable?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: new integration variable

Hi;

This is less clear than your first question what are you trying to do with:

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.