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## #1 2010-04-29 23:34:56

sousou
Member
Registered: 2010-04-29
Posts: 5

### I need your help to expand the following:

Hello,

I need your help to expand the following:

A = sqrt [C^2 + L^2 - 2*C*L cos (theta + phi)]

Where:    C = sqrt[L^2 + (X + Y)^2]
phi = atan[(X+Y)/L]

L is a constant.

Thanks for your help and time.

Last edited by sousou (2010-04-29 23:35:59)

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## #2 2010-04-30 00:52:28

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: I need your help to expand the following:

Hi sousou;

This is the best I can do after 3 tries :

A little simpler:

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.

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## #3 2010-04-30 01:05:40

sousou
Member
Registered: 2010-04-29
Posts: 5

### Re: I need your help to expand the following:

bobbym wrote:

Hi sousou;

This is the best I can do after 3 tries :

A little simpler:

Thanks Bobby,

could you please show the detailed workout o fthe three tries ...Thanks...

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## #4 2010-04-30 02:21:10

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: I need your help to expand the following:

Hi sousou;

There isn't anything to show just the 2 substitutions and a small cleanup. I didn't do very much here.

Pull out a factor of 2L inside the radical:

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.

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## #5 2010-04-30 02:26:12

sousou
Member
Registered: 2010-04-29
Posts: 5

### Re: I need your help to expand the following:

bobbym wrote:

Hi sousou;

There isn't anything to show just the 2 substitutions and a small cleanup. I didn't do very much here.

Pull out a factor of 2L inside the radical:

Thanks lobby,

but all what you did is substitution

I am looking for further simplification, I wanna get rid of the square root :

A = sqrt [C^2 + L^2 - 2*C*L cos (theta + phi)] = A = [C^2 + L^2 - 2*C*L cos (theta + phi)]^1/2///

and then expand the polynomial...

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## #6 2010-04-30 02:31:18

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: I need your help to expand the following:

Hi sousou;

That is not a polynomial. How do you plan to expand it:

You could expand it as a Taylor series but that is all , I think.

I haven't worked on simplifying the terms underneath the radical. What I have in post # 4 might be all that is possible.

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.

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## #7 2010-04-30 03:08:04

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

### Re: I need your help to expand the following:

Hence

Last edited by JaneFairfax (2010-04-30 03:16:53)

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## #8 2010-04-30 03:27:52

sousou
Member
Registered: 2010-04-29
Posts: 5

### Re: I need your help to expand the following:

Thanks ....I wonder how you could write the symbols of maths? is it the same sythax as lateX?

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## #9 2017-10-04 15:51:56

Monox D. I-Fly
Member
From: Indonesia
Registered: 2015-12-02
Posts: 1,047

### Re: I need your help to expand the following:

sousou wrote:

Thanks ....I wonder how you could write the symbols of maths? is it the same sythax as lateX?

Yes.

Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away. May his adventurous soul rest in peace at heaven.

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