# Need help transposing an equation!!

• Feb 26th 2010, 01:39 PM
Need help transposing an equation!!
Hi there,

I need help transposing the equation for electrical resonance.

The equation is f = 1 / 2*pi * squareroot of L*C

I need to make C the subject, any help would be greatly appreciated.
• Feb 26th 2010, 01:46 PM
TKHunny
Quote:

Originally Posted by nleadbet
The equation is f = 1 / 2*pi * squareroot of L*C

1) Multiply by 2
2) Divide by $\displaystyle \pi$
3) Square, and remember that L*C > 0
4) Divide by L

I need to know why you were struggling with this.
• Feb 26th 2010, 01:47 PM
Bacterius
Now this is ambigious. Pick the right one :

$\displaystyle f = \frac{1}{2} x \pi x \sqrt{L(x) C}$

$\displaystyle f = \frac{1}{2} x Pi(x) \sqrt{L(x) C}$

$\displaystyle f = \frac{1}{2x} \pi x \sqrt{L(x) C}$

$\displaystyle f = \frac{1}{2x} Pi(x) \sqrt{L(x) C}$

Or just edit your post with the right one. Use the [tex] tags to write it in LaTeX with the pretty symbols and all.

EDIT : ah you edited it somehow before I posted. Well, as TkHunny said, just use division/multiplication/squares to put this in order :)
• Feb 26th 2010, 01:50 PM
TKHunny
Quote:

Originally Posted by nleadbet
Hi there,

I need help transposing the equation for electrical resonance.

The equation is f = 1 / 2*pi * squareroot of L*C

I need to make C the subject, any help would be greatly appreciated.

...or is it $\displaystyle \frac{1}{2\pi}\sqrt{L\cdot C}$?

The very first thing would be to write carefully so that you can communicate.
• Feb 26th 2010, 03:02 PM
satx
Is C part of the radical or not? Also, is everything after the / sign in the denominator or is it (1/2)(pi*...)?
• Feb 26th 2010, 03:23 PM
e^(i*pi)
From the actual question we get

$\displaystyle \omega = 2 \pi f = \frac{1}{\sqrt{LC}}$

Manipulating to get f we get the original question

$\displaystyle f = \frac{1}{2\pi \sqrt{LC}}$

Multiply by $\displaystyle 2\pi$
$\displaystyle 2\pi f = \sqrt{LC}$
Square both sides, then divide by L

$\displaystyle C = 4 \pi ^2 \cdot \left(\frac{f^2}{L}\right)$
• Feb 27th 2010, 11:41 AM
Quote:

Originally Posted by e^(i*pi)
From the actual question we get

$\displaystyle \omega = 2 \pi f = \frac{1}{\sqrt{LC}}$

Manipulating to get f we get the original question

$\displaystyle f = \frac{1}{2\pi \sqrt{LC}}$

Multiply by $\displaystyle 2\pi$
$\displaystyle 2\pi f = \sqrt{LC}$
Square both sides, then divide by L

$\displaystyle C = 4 \pi ^2 \cdot \left(\frac{f^2}{L}\right)$

Thanks alot for all your help, its been a good 20 years sonce I've done any algebra!!