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    find the range of values for k for which the equation x^2-kx+(k+3)=0
    please help the ks have confused me
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    (Original post by p29)
    find the range of values for k for which the equation x^2-kx+(k+3)=0
    please help the ks have confused me
    lol

    Show your working.
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    (Original post by RDKGames)
    lol

    Show your working.
    apparantly the answer is k< -2 or k>6
    HOW?!?!?! The signs have have a line under them btw (less than and equal to)
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    (Original post by p29)

    apparantly the answer is k< -2 or k>6
    HOW?!?!?! The signs have have a line under them btw (less than and equal to)
    :facepalm:

    That equation is valid when the roots are real, that's like the first thing in C1. So:

    b^2-4ac \geq 0

    a=1
    b=-k
    c=k+3

    Good luck
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    (Original post by RDKGames)
    :facepalm:

    That equation is valid when the roots are real, that's like the first thing in C1. So:

    b^2-4ac \geq 0

    a=1
    b=-k
    c=k+3

    Good luck
    thank you
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    (Original post by RDKGames)
    :facepalm:

    That equation is valid when the roots are real, that's like the first thing in C1. So:

    b^2-4ac \geq 0

    a=1
    b=-k
    c=k+3

    Good luck
    why did you equal it to 0?
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    (Original post by RDKGames)
    :facepalm:

    That equation is valid when the roots are real, that's like the first thing in C1. So:

    b^2-4ac \geq 0

    a=1
    b=-k
    c=k+3

    Good luck
    and why did you not use the full quadratic formula?
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    (Original post by p29)
    why did you equal it to 0?
    (Original post by p29)
    and why did you not use the full quadratic formula?
    Look at your C1 book for those answers.
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    (Original post by RDKGames)
    Look at your C1 book for those answers.
    k.
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    (Original post by RDKGames)
    Look at your C1 book for those answers.
    You come across as a stuck up imbecile btw
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    (Original post by Squishy•)
    You come across as a stuck up imbecile btw
    Hard not to. You must've missed a few weeks back when this same guy asked why a minus multiplied by a minus is a plus. After like 6 different ways to think about it, and well explained ways, he still didn't get it. He is now doing AS Maths.

    Troll? Maybe.
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    (Original post by p29)
    and why did you not use the full quadratic formula?
    If b^2-4ac is less than zero then the quadratic formula doesn't work as in the formula it's the square root of b^2-4ac. So it has to be positive for you to be able to take a square root and therefore for there to be values to the equation.
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    (Original post by RDKGames)
    Hard not to. You must've missed a few weeks back when this same guy asked why a minus multiplied by a minus is a plus. He is now doing AS Maths.
    Oh well, don't ridicule someone for asking questions. They're trying to understand so how can you put someone down for that.
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    (Original post by Squishy•)
    If b^2-4ac is less than zero then the quadratic formula doesn't work as in the formula it's the square root of b^2-4ac. So it has to be positive for you to be able to take a square root and therefore for there to be values to the equation.
    thank you
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    (Original post by Squishy•)
    Oh well, don't ridicule someone for asking questions. They're trying to understand so how can you put someone down for that.
    Because it's hard to say when they're trolling or not. This is something he should've learnt about if he's attempting these questions therefore he should understand the significance of the discriminant. If not, his book explains it pretty well so I don't have to.

    (Original post by Squishy•)
    If b^2-4ac is less than zero then the quadratic formula doesn't work as in the formula it's the square root of b^2-4ac. So it has to be positive for you to be able to take a square root and therefore for there to be values to the equation.
    It does work if it's negative, you just would't get real roots. His question doesn't specify that k has to be real. If we assume it is, then the discriminant must be 0 or greater in order to prevent complex roots and stay within reals.
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    (Original post by RDKGames)
    Hard not to. You must've missed a few weeks back when this same guy asked why a minus multiplied by a minus is a plus. After like 6 different ways to think about it, and well explained ways, he still didn't get it. He is now doing AS Maths.

    Troll? Maybe.
    Still bitter I see
    lol.
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    (Original post by p29)
    Still bitter I see
    lol.
    Yes

    :slap:
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    (Original post by RDKGames)
    Because it's hard to say when they're trolling or not. This is something he should've learnt about if he's attempting these questions therefore he should understand the significance of the discriminant. If not, his book explains it pretty well so I don't have to.



    It does work if it's negative, you just would't get real roots. His question doesn't specify that k has to be real. If we assume it is, then the discriminant must be 0 or greater in order to prevent complex roots and stay within reals.
    I said the quadratic formula wouldn't work if it's negative, which it doesn't. Why the hell would you assume imaginary numbers in this question, you even mentioned C1.

    If they were trolling then you don't even need to comment. They weren't asking you directly and so the idea of you having to teach him isn't even in the question. No one has to do anything on here. The book may explain it but he posted on here to get an answer from here so if you don't want to help them without belittling them then you best not respond in the first place.

    Also questioning why a - x - = + isn't wrong or crazy either. They are questioning something which has only been taught as a convention so that's reasonable.
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    (Original post by Squishy•)
    I said the quadratic formula wouldn't work if it's negative, which it doesn't. Why the hell would you assume imaginary numbers in this question, you even mentioned C1.

    If they were trolling then you don't even need to comment. They weren't asking you directly and so the idea of you having to teach him isn't even in the question. No one has to do anything on here. The book may explain it but he posted on here to get an answer from here so if you don't want to help them without belittling them then you best not respond in the first place.

    Also questioning why a - x - = + isn't wrong or crazy either. They are questioning something which has only been taught as a convention so that's reasonable.
    It does work if the discriminant is negative. Well he didn't specify it was from C1, I only mentioned that it is the module in which you touch upon this concept, doesn't mean the question is strictly from that module.

    I still showed him where the answers come from.

    Yeah, questioning why - x - = + is not crazy or wrong, and I never implied so, but the fact that different explanations do not get the idea across is a bit strange indeed.
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    (Original post by RDKGames)
    It does work if the discriminant is negative. Well he didn't specify it was from C1, I only mentioned that it is the module in which you touch upon this concept, doesn't mean the question is strictly from that module.

    I still showed him where the answers come from.

    Yeah, questioning why - x - = + is not crazy or wrong, and I never implied so, but the fact that different explanations do not get the idea across is a bit strange indeed.
    U are being very petty
 
 
 
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