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anonymous

  • 5 years ago

u/(u-(u+1/2))=4

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  1. anonymous
    • 5 years ago
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    \[u\left/\left(u-\left(\frac{1}{2}+u\right)\right)\right.\text{=}4\]\[u\left/\left(-\frac{1}{2}\right)\right.\text{=}4\]\[-2 u\text{ = }4\]\[u\to -2 \]

  2. gw2011
    • 5 years ago
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    u/[u-(u+1/2)]=4 u/(u-u-1/2)=4 u/-1/2=4 -2u=4 u=-2

  3. anonymous
    • 5 years ago
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    answer book says the answer is 2...

  4. gw2011
    • 5 years ago
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    Either the answer book is wrong or the problems is written incorrectly. Since 1/2 is -1/2, you will get a negative u.

  5. gw2011
    • 5 years ago
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    If you substitute what the answer book has, then the answer will be -4 and not 4.

  6. anonymous
    • 5 years ago
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    well... i'm having trouble writing an equation like this on the computer. but the (u-(u+1/2) is written as u - u +1 over 2.... make sense?

  7. gw2011
    • 5 years ago
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    With the negative in front of (u+1/2), then u becomes -u and the +1/2 becomes -1/2.

  8. anonymous
    • 5 years ago
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    i wish i could figure out the equation thing the u+1 is over the 2. and you're subtracting the whole thing from u...

  9. gw2011
    • 5 years ago
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    If the equation is meant to be the following: u/(u-u+1/2)=4 then u=2 is correct.

  10. anonymous
    • 5 years ago
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    i guess i need to figure out the equation button and re-post my question

  11. anonymous
    • 5 years ago
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    Plug in 2 for u in the problem expression. At the end of the evaluation process Mathematica tells us that -4=+4, an invalid outcome. So u is not 2.\[\frac{u}{u-\left(u+\frac{1}{2}\right)}==4\text{/.}u\to 2 \]\[\frac{2}{2-\left(2+\frac{1}{2}\right)}==4 \]\[\frac{2}{2-\frac{5}{2}}==4 \]\[\frac{2}{\left(-\frac{1}{2}\right)}==4\]\[-4==4 \]

  12. anonymous
    • 5 years ago
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    the (u+1/2) is not written correctly. it's (u+1)over 2. make sense?

  13. gw2011
    • 5 years ago
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    According to your latest equation that (u+1)/2, then the equation should be as follows: u/[u-(u+1)/2]=4 u/[(2u-u-1)/2=4 u/[(u-1)/2]=4 (u)[2/(u-1)]=4 2u/(u-1)=4 2u=4(u-1) 2u=4u-4 You can rewrite this equation as: 4u-4=2u 2u=4 u=2

  14. anonymous
    • 5 years ago
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    my apologies for mistyping the equation initially

  15. anonymous
    • 5 years ago
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    "the (u+1/2) is not written correctly. it's (u+1)over 2. make sense?" The common convention in computer land is that multiplication and division take precedence over addition and subtraction. So I interpreted the subexpression of concern the way it was presented in my solution derivation. I don't want to ruffle any feathers here, but nearly half the time the math expressions presented as problems on this web site are, strictly speaking, ambiguous. Hence the back and for over what the intent of your problem expression was. Notice that you added an addition ")" after the u+1 that was not in the original problem statement. I use Mathematica 8 for calculations and normally send all math problem statements to WolframAlfa.com for their interpretation of the problem statements. Mathematica 8 has a direct connection with WoframAlfa through a drop down menue selection, " Free- form input" for this purpose. I guess this is an example of "Cloud computing." This is all I have to say on this matter. Have a good day.

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