Math Is Fun Forum

rvdude

Member

Registered: 2012-10-24

Posts: 3

Solve for the variable L?

Here is my problem:

w squared = (1/LC) - (R squared / L squared)

I need to solve for the variable L.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Solve for the variable L?

Hi;

I am assuming this is what you want to solve:

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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.

rvdude

Member

Registered: 2012-10-24

Posts: 3

Re: Solve for the variable L?

This is very interesting because your first equation with the "1 +" gives me an incorrect value, but your second equation with the "1 -" gives me the correct value!!! So I'm surmising that the 2nd equation is the correct one that will always work??? And, could you please direct me to the type of math you used to obtain your results? Is this algebra, calculus or what???

And thank you very much for your help!!

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Solve for the variable L?

Hi;

Every quadratic equation has two solutions. In math they both apply and there is no reason to favor one over the other. In practical problems one answer may be ridiculous. Like getting a negative area or a negative weight. It is not necessarily true that one answer will always be the only one.

This is called algebra.

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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.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Solve for the variable L?

Yes, Quadratic Equations are like that. See the first example here: Mathematical Models 2

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman