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ganeshie8

  • 2 years ago

i am getting two solutions for this problem. but only one is satisfying the equation. could someone pls explain whats going on... http://assets.openstudy.com/updates/attachments/50064e0ae4b0624180677e0a-emily9102-1342590484915-mathproblem5.jpg

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  1. f1r1e1s1h1
    • 2 years ago
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    square it and try?

  2. ganeshie8
    • 2 years ago
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    |dw:1342591850277:dw|

  3. ganeshie8
    • 2 years ago
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    x =1 is not satisfying the equation :( not sure why

  4. ganeshie8
    • 2 years ago
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    hmm

  5. f1r1e1s1h1
    • 2 years ago
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    man u have squared it so ofcourse one will not match?

  6. higgs
    • 2 years ago
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    when you square something, you will always get two solutions, and not all of them will be right. substitute the answers back into the original equation to check. in this case, 1 is not the solution as -1 is not equal to 1

  7. ganeshie8
    • 2 years ago
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    im li'l lost.... could u elaborate pls.. ?

  8. ganeshie8
    • 2 years ago
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    i see we are squaring... and losing sign sensitivity is it

  9. mukushla
    • 2 years ago
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    u must consider restrictions in every step note that when u have \( x-3=2 \sqrt{x} \) then \( x-3 \ge0 \)

  10. ganeshie8
    • 2 years ago
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    ah that makes sense. thanks mukushla straight to the point. :)

  11. mukushla
    • 2 years ago
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    welcome my friend

  12. higgs
    • 2 years ago
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    I suppose this also applies to irrational equations like this? \[\sqrt{x-1}+\sqrt{x+4}=\sqrt{3x+10}\] I got \(x = 5\) and \(x = \frac{-13}{3} \) \(x = \frac{-13}{3} \) is rejected in this case as well because after substituting into the equation, it became undefined.

  13. ganeshie8
    • 2 years ago
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    yeah now i understand thanks higgs :D here, from the first equation itself, we can apply the restriction x >=1. and hence rejected solutions < 1

  14. No.name
    • 4 months ago
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    The sollutions we get after solving , and which does not satisfy the origanal question are called extraneous sollutions. There occurred as we have squared , so there is a chance of getting a extraneous sollution.

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