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Old 12-08-2009, 16:30   #1
nVid
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Quick Inverse Function

What is the inverse 1/x+1

( one, divided by x plus one)

Cheers
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Old 12-08-2009, 18:20   #2
Fremen
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1/x+1 = y

Now solve for x, and that's the inverse as a function of y.
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Old 12-08-2009, 20:25   #3
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Perhaps I'm overthinking it, but are you trying to show

for

i.e. a convergent geometric series. If not, then nevermind
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Old 12-08-2009, 23:15   #4
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Quote:
Originally Posted by Fremen View Post
1/x+1 = y

Now solve for x, and that's the inverse as a function of y.
I have forgot if the +1 stays under the divide line.

x = 1/y+1 ?

too late at night
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Old 12-08-2009, 23:17   #5
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Try it with actual numbers and see which way works
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Old 13-08-2009, 16:50   #6
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Quote:
Originally Posted by Fremen View Post
Try it with actual numbers and see which way works
I have a feeling your familiar with problem based learning.

I realy need to brush up on the basic manipulation of formulae.

Anywhere online that has a page about it, or you seem proficient can you give a few examples.

AB = C -> A = C/B

Somthing like that?

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Old 13-08-2009, 20:54   #7
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Quote:
Originally Posted by nVid View Post
What is the inverse 1/x+1

( one, divided by x plus one)

Cheers
I probably shouldn't be doing this - it's b etter for you if you can figure it out yourself, but here goes:

1/(x+1) = y

Now cross-multiply to get

1 = y(x+1)

Multiply out the right-hand-side to get:

1 = xy + y

Now, you want the term involving x to be on it's own on one side, therefore you get:

1 - y = xy

Finally divide both sides by y (to get rid of the y on the right, leaving just x) to get

(1 - y) / y = x

That's your answer.
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