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March 23rd, 2013, 08:27 AM   #1
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Changing the subject of a formula

Find r when V = 4/3?r^3

Next I have multiplied by 3 giving

3V = 4?r^3

Then divide by 4? giving

r^3 = 3V/4?

Here is where I am not sure, do I cube root both sides?

Like r = cube root 3v/4?

Thanks in advance.
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March 23rd, 2013, 09:11 AM   #2
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Re: Changing the subject of a formula

Quote:
Originally Posted by adamfoley
Find r when V = 4/3?r^3
Next I have multiplied by 3 giving
3V = 4?r^3
Then divide by 4? giving
r^3 = 3V/4?
Here is where I am not sure, do I cube root both sides?
Like r = cube root 3v/4?
This would be clearer: V = (4/3)?r^3 or V = 4?r^3 / 3

Apart from that, all's fine; good stuff!
Show this way: r = [3v / (4?)]^(1/3)
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March 23rd, 2013, 02:05 PM   #3
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Re: Changing the subject of a formula

Thanks for the reply Denis, that clears things up.
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