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    \sqrt{x^2+40^2} the same as {x+40}? I dont think it is the same, but i dont understand why it is not the same.

    Pangol RDKGames Notnek
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    (Original post by Dexter212)
    \sqrt{x^2+40^2} the same as {x+40}? I dont think it is the same, but i dont understand why it is not the same.

    Pangol RDKGames Notnek
    You're right they're not the same.

    If they were the same then (x+40)^2 = x^2+40^2. Can you see why this is false?

    There is no law for \sqrt{A+B} like there is for \sqrt{AB} = \sqrt{A}\times \sqrt{B} for example.
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    (Original post by Dexter212)
    \sqrt{x^2+40^2} the same as {x+40}? I dont think it is the same, but i dont understand why it is not the same.

    Pangol RDKGames Notnek
    It's not the same, no. The easiest way to see this is to say that if they were equal, you would get the same thing if you squared both of them. If you square the first version, you get x^2 + 40^2. What do you get if you square x + 40 ?
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    You have to work out what’s under the square root first, hence some people put brackets under square root signs. Take root(4+9) as an example. By your logic it would give 2+3 which equals 5. In reality it’s asking for root(13) which is a surd...
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    (Original post by Notnek)
    If they were the same then (x+40)^2 = x^2+40^2. Can you see why this is false?
    Great minds...
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    (Original post by Pangol)
    Great minds...
    ...do maths.
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    I suggest putting in some simple numbers. This can help you see that they are not the same:

    \sqrt{3^2+4^2} = \sqrt{9+16} = \sqrt{25} = 5

    However:

     3 + 4 = 7

    5 and 7 are different, so this proves that they are not the same.
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    (Original post by Notnek)
    You're right they're not the same.

    If they were the same then (x+40)^2 = x^2+40^2. Can you see why this is false?

    There is no law for \sqrt{A+B} like there is for \sqrt{AB} = \sqrt{A}\times \sqrt{B} for example.
    So...
    \sqrt{x^2+40^2} is not equal to \sqrt{x^2}+\sqrt{1600} ?
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    (Original post by joyoustele)
    So...
    \sqrt{x^2+40^2} is not equal to \sqrt{x^2}+\sqrt{1600} ?
    Correct.
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    (Original post by Notnek)
    Correct.
    Got it, Thanks all.
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    (Original post by joyoustele)
    Got it, Thanks all.
    Are you the OP?
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    (Original post by Notnek)
    Are you the OP?
    Yes.
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    (Original post by joyoustele)
    Yes.
    Please try to stick to one account so people don't get confused
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    (Original post by Notnek)
    Please try to stick to one account so people don't get confused
    Okay
 
 
 
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