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    Could anyone help I'm stuck on question 4 part iii on this paper
    https://7c95ed1f832973eac0c6e1a52b08...20C3%20OCR.pdf

    I'm not even sure I understand the question, and I have no idea how the answer
    '0 < k <= 2' relates to the question because i thought the equation f(x) = 2 - x^(1/2) only had one root
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    (Original post by JW22)
    Could anyone help I'm stuck on question 4 part iii on this paper
    https://7c95ed1f832973eac0c6e1a52b08...20C3%20OCR.pdf

    I'm not even sure I understand the question, and I have no idea how the answer
    '0 < k <= 2' relates to the question because i thought the equation f(x) = 2 - x^(1/2) only had one root
    Since the function is strictly decreasing (see the graph or differentiate), in order for there to be two distinct roots, we must have f(x_1)=k and f(x_2)=-k, as then |f(x_1)|=|f(x_2)|=k.
    Can you see now why the given range is the answer?
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    (Original post by joostan)
    Since the function is strictly decreasing (see the graph or differentiate), in order for there to be two distinct roots, we must have f(x_1)=k and f(x_2)=-k, as then |f(x_1)|=|f(x_2)|=k.
    Can you see now why the given range is the answer?
    Yes thanks!
 
 
 
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