Math Is Fun Forum

BarandaMan

Guest

Rearranging Urgent Help!! Part 2

Hi there!

This step in the textbook has had me stumped

tinypic.com/r/24359up/5

So there is one term on the RHS which clearly makes a lot of sense, but then somehow, there is a Pi* and (Pi - Pi*) term, broken down from the initial term. We require it in this format to show inflation bias, just incase you are interested. But I cannot seem to find a way to make it like that.

Please help :D

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Rearranging Urgent Help!! Part 2

Hi;

That is correct, what have you tried?

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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.

BarandaMan

Guest

Re: Rearranging Urgent Help!! Part 2

Hi;

That is correct, what have you tried?

You did it that quickly? Oh my....

I have tried expanding the RHS, splitting them up into three terms each with the same denominator. I worked backwards (cheated) from the answer to try and saw that:

aPi*=Pi*(a+b^2-b^2) = Pi*(1 - (b^2)/a+b^2) = Pi* - (Pi*b^2/a+b^2) which is the term, but I do not know how I would have got there without the answer to go back from. Does this make sense?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Rearranging Urgent Help!! Part 2

Hi;

I am working on it, so far I am not getting it either.

---

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.

BarandaMan

Guest

Re: Rearranging Urgent Help!! Part 2

Hi;

I am working on it, so far I am not getting it either.

Ok thank you. Don't spend too long on it if it is too much hassle, I do not mind going backwards in the exam

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Rearranging Urgent Help!! Part 2

Hi;

The only thing I can think of is he used this identity here.

Why he wanted to? I do not know.

---

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.

BarandaMan

Guest

Re: Rearranging Urgent Help!! Part 2

Oh my, but this identity works with this example completely? I think I should study all of the identities.... you are incredible, again, bobby!
Haha (and still a genius...)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Rearranging Urgent Help!! Part 2

Him using that identity is very weird. I have no idea why he wanted to get the

together. The original equation was fine.

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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.