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sugarheart

  • 2 years ago

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  1. Mertsj
    • 2 years ago
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    The deal is this....when you square an equation you sometimes end up with a "solution" that doesn't make the sentence true. Those are called extraneous roots. They are the reason your teacher tells you to always check the answers you get when solving radical equations. Sometimes they don't work. Let me show you an example.

  2. Mertsj
    • 2 years ago
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    |dw:1366677654241:dw|

  3. precal
    • 2 years ago
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    also, the domain helps in identifying extraneous solutions

  4. Mertsj
    • 2 years ago
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    And that answer will not check. It is an extraneous solution.

  5. sugarheart
    • 2 years ago
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    I got it, it's 5

  6. Mertsj
    • 2 years ago
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    You solved your problem?

  7. sugarheart
    • 2 years ago
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    Yes

  8. Mertsj
    • 2 years ago
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    Good for you!!!

  9. Mertsj
    • 2 years ago
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    Hey...just a minute. I don't think 5 will check.

  10. Mertsj
    • 2 years ago
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    |dw:1366677868347:dw|

  11. Mertsj
    • 2 years ago
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    Some graduate student made a grievous error in writing your question.

  12. sugarheart
    • 2 years ago
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    What?

  13. Mertsj
    • 2 years ago
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    As you can see...5 does not make the sentence true.

  14. Mertsj
    • 2 years ago
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    So if 5 was accepted as a correct answer, someone has put the wrong answer into the computer program .

  15. Mertsj
    • 2 years ago
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    Didn't you also get -3 as an answer?

  16. precal
    • 2 years ago
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    you mean |dw:1366678251238:dw|

  17. sugarheart
    • 2 years ago
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    @precal Why does that matter though.. It wasn't my question it was his example

  18. Mertsj
    • 2 years ago
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    |dw:1366678291957:dw|

  19. precal
    • 2 years ago
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    because 13 is extraneous

  20. Mertsj
    • 2 years ago
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    You see...-3 is actually an answer. It checks. 5 is extraneous.

  21. Mertsj
    • 2 years ago
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    @precal That was an example I constructed to illustrate extraneous roots for the asker

  22. precal
    • 2 years ago
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    sorry Mertsj, saw your example and not the actual problem

  23. Mertsj
    • 2 years ago
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    np

  24. precal
    • 2 years ago
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    Key idea @sugarheart is that when solving solutions for square root equations or radicals, extraneous solutions do exist so we have to check for them

  25. sugarheart
    • 2 years ago
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    5 is the extraneous solution and that's why it's was the answer to my problem

  26. Mertsj
    • 2 years ago
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    oh. So they were asking for the extraneous root. Cool. Then it is right.

  27. sugarheart
    • 2 years ago
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    Yes lol

  28. Mertsj
    • 2 years ago
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    Yep. I reread the question. Always helps to know the question one is attempting to answer.

  29. precal
    • 2 years ago
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    extraneous solutions can also, occur in other functions (example logarithmic)

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