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'[OT]: Help with math problem'
2002\10\02@141834 by

First, how do you show superscript in text messages?
I'll be using HTML tags to indicate superscript (<sup></sup>)

I can't the correct result from this equation:
C = (0.09*E*t <sup>2</sup> /K <sup>4</sup> )<sup>1/3</sup>
If E=100, t=500 microsecs (500E-6), and K=13
then:
C=[0.09*100*(500E-6)<sup>2</sup>/(13)<sup>4</sup>]<sup>1/3</sup>
is what?

I keep on getting 0.422E-3 Farad.
Where did I go wrong or is it them?

Maybe it is getting too late here.

Thanks
Quentin

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To denote an exponent, use the caret (^):

C = [(0.09 * E * t^2) / (K^4)]^1/3

= [(0.09 * 100 * (5e-4)^2) / (13^4)]^1/3

The answer I get is 4.29e-5.

If t = 5us instead of 500us, I get .199e-4 (or 1.99e-5).

My two troubleshooting questions:
Are you sure of your exponent values (e-3 vs. e-4)?
Are you sure of the values you are plugging into the equation? (esp. t)

BTW, textbooks are occasionally wrong.  Then again, so am I.  :)

Jen

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Quentin,

dimensional analysis doesn't work).  Commonly, I've seen carat ^ or
double asterisk ** used to indicate exponentiation.  As always,
parentheses can be used to clarify.

Regards,
Dave

Quentin wrote:
{Quote hidden}

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> The answer I get is 4.29e-5.
I get 0.429e-3. I got 0.422e-3 in my previous post because I used 0.334
as a replacement for 1/3.

> If t = 5us instead of 500us, I get .199e-4 (or 1.99e-5).
Yes, I looked back in the document and it stated that t should be in the
range of 5 to 50 microsecs.

So the text example is incorrect, I can merrily plod along with my own
values.
Thanks Jen, and Dave for confirming it.

Quentin

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