Question

[(1/x) - (1/y)] / [(1/x) + (1/y)]
Help?

Answer 1

Explain pleasee.?

Answer 2

Common Denominator: xy

y/xy - x/xy
(x - y)/xy TOP
(x + y)/xy Bottom

Flip to multiply

(x-y)/(xy) (xy)/(x+y)

(y-x)/(x+y)

Answer 3

I usually go an algebra route and do this: then solve and simplify for N
\[\frac{(1/x) - (1/y)}{(1/x) + (1/y)}=N\]

Answer 4

hey! my answer?

Answer 5

Interesting strategy amistre64, I use that to solve for logarithms with odd bases and no calculator.

Answer 6

When working with complex fractions, I prefer to simplify them first.
LCD of the inner fractions is xy
\[\frac{(1/x) - (1/y)}{(1/x) + (1/y)}\]\[=\frac{(1/x) - (1/y)}{(1/x) + (1/y)} \cdot \frac{xy}{xy}\]\[=\frac{y - x}{y + x}\]

Answer 7

So whenever you have a complex fraction you can simplify by multiplying the top/bottom of the outer (larger) fraction by the LCD of all the inner fractions

Answer 8

\[\frac{(1/x) - (1/y)}{(1/x) + (1/y)}=N\]
\[(1/x) - (1/y)=N((1/x) + (1/y))\text{ ; clear fractions}\]
\[1 - (x/y)=N(1 + (x/y))\text{ ; clear fractions again}\]
\[y - x=N(y + x))\text{ ; divide out the (y+x)}\]
\[\frac{y - x}{y+x}=N\text{ ; tada!! :)}\]

Answer 9

where did my answer go? did any one delete it?

Answer 10

i havent seen it ....

Answer 11

I saw it briefly

Answer 12

i replied first
when kait said explain please before that

Answer 13

then some1 replied so i didnt explain

Answer 14

bur my answer is removed

Answer 15

Thank you guys!!(: & no, i didnt delete it, thats what I was looking at, I couldnt find it. xD

Answer 16

I often delete answers that have no explanation or justification. It doesn't help the user, it can be easily found using wolframalpha. If you want to help people, help them. Don't give them answers.

Answer 17

yes but you should not do that polpak.. i generally answer and ask if the user wants me to explain and then i explain..... or should i change my technique then?

Answer 18

You should assume that they want an explanation. If they don't they should be using wolframalpha to check their answers (or cheat).

Answer 19

okay...

Answer 20

This is upsetting. But you're fine guys, you're helping me out alot. You're the only three or four people that ever answer my questions anyways.(:

Answer 21

kait nothing to be upset of.. All of us are here to help.. All the people ill help you.. I just asked polpak to confirm if he deleted my answer n nothing

Answer 22

I don't think anyone's upset. Or at least I'm not. Just a bit of administrivia that happened to occur in your question. Not a big deal.

Answer 23

right:)