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    f is defined by f : x --> e^x +k

    1. state the range of f
    2. find(ln k)

    I don't understand, please help x
    pretty please
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    think about the values e^x can take: if necessary, draw the graph. Then work out which values e^x +k can take (this depends on the value of the constant k)
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    The range is the set of values that f can take.

    For example, say we have g:x \mapsto x^2+3. Since x^2 \ge 0 for any value of x, we must have x^2 + 3 \ge 3, and so g(x) \ge 3 is the range. So what is the range here?

    For Q2 I think you must have missed out part of the question because we can't find \ln k without knowing what e^x+k is equal to.
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    for the 2nd part, is there any extra context?
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    thanks for all the help so far
    question 2 in full:
    "f:x --> e^x +k, xER, and k is a positive constant.
    find f(lnk)"
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    (Original post by nuodai)
    The range is the set of values that f can take.

    For example, say we have g:x \mapsto x^2+3. Since x^2 \ge 0 for any value of x, we must have x^2 + 3 \ge 3, and so g(x) \ge 3 is the range. So what is the range here?

    For Q2 I think you must have missed out part of the question because we can't find \ln k without knowing what e^x+k is equal to.
    x > k?
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    (Original post by pete.mcfc)
    find f(lnk)"
    Right! That's not what you said

    When you have f(x) and you need to find f(\text{something}), there are three simple steps you need to follow:
    1. Write out the expression for f(x). In this case f(x) = e^x+k
    2. Replace any occurrence of "x" with "(x)", so here we have e^{(x)}+k
    3. Replace what's inside the brackets with the "something"
    ...then simplify if necessary.

    Step #2 isn't really necessary, but it's useful when you're learning how to do these things for the first time (it's easy to make silly mistakes).

    (Original post by pete.mcfc)
    x > k?
    Yup
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    (Original post by nuodai)
    Right! That's not what you said

    When you have f(x) and you need to find f(\text{something}), there are three simple steps you need to follow:
    1. Write out the expression for f(x). In this case f(x) = e^x+k
    2. Replace any occurrence of "x" with "(x)", so here we have e^{(x)}+k
    3. Replace what's inside the brackets with the "something"
    ...then simplify if necessary.

    Step #2 isn't really necessary, but it's useful when you're learning how to do these things for the first time (it's easy to make silly mistakes).


    Yup
    haha sorry about that but thanks, rep for you and Mc^3 when I can spread the love

    e^(ln k ) + k
    do e and ln cancel leaving 2k?
    Sorry if I'm being stupid/frustrating
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    they do indeed
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    (Original post by Mc^3)
    they do indeed
    both legends thanks x
 
 
 
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