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#1 WinkyCode  Icon User is offline

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Mind-block in algebra about exponentiation

Posted 27 June 2013 - 12:56 PM

Hello dear coders,

I am studying math now and it is numeric math followed by algebra, then trigonometric and finally some LaTeX coding. Now, I have a mind-block about a thing.

If 1/X is X^(-1), then is 5/X = X^(-5)? According to questions like (x^2+6x+4)(x^3-9x+5/x), I keep getting the wrong answers. My block is the 5/X. The rest I am pretty sure of.

Thank you for taking the time to look at my thread :) .

Kind regards
Winky

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Replies To: Mind-block in algebra about exponentiation

#2 jon.kiparsky  Icon User is offline

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Re: Mind-block in algebra about exponentiation

Posted 27 June 2013 - 01:15 PM

Quote

If 1/X is X^(-1), then is 5/X = X^(-5)


No, not quite. 5^(-n)= 1/(5^n)


Think about ordinary place-based integer notation: 123.45 =

1* 10^2 + 2* 10^1 + 3 *10^0 + 4*10^-1 + 5* 10^-2 (and so forth)

So clearly 10 ^-2 = .01 = 1/(10^2)

I hope that helps.
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#3 CSatVTftw  Icon User is offline

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Re: Mind-block in algebra about exponentiation

Posted 10 July 2013 - 05:44 PM

a number to (-1) can be written as one over the number, so if you have 5/x it's the same as saying 5 * (1/x). So bring your x to the top by making it a negative exponent and you get 5*x^(-1).
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#4 WinkyCode  Icon User is offline

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Re: Mind-block in algebra about exponentiation

Posted 10 July 2013 - 11:33 PM

Thank you CSatVTftw. It solved my mind-block. :bananaman:

Solution:
5/x gives 5x^(-1) or a/x = a*x^(-1)
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