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-   -   How do you find f(f(g(x)))... If f(x) = 2x+5 and g(x)= square root of x (https://www.askmehelpdesk.com/showthread.php?t=568637)

  • Apr 7, 2011, 12:44 PM
    Mandeep100
    How do you find f(f(g(x)))... If f(x) = 2x+5 and g(x)= √x
    2. Given f(x) = k(2+x), find the value of k if f^-1 (-2) = -3

    3. Consider the following function:
    f(x) = -2 all square (-x + 4) -3 find the equation of the inverse function

    One you graph f(x) and its inverse on a grid

    find Df, D f-1, Rf, R f-1
  • Apr 7, 2011, 02:20 PM
    galactus

    I will try to decipher.

    Quote:

    2.
    Replace f(x) with y:



    swap x and y:

    .

    Solve for y.

    Then, sub in x=-2, set the equation equal to -3 and solve for k.


    Quote:

    3. Find the inverse of
    Replace f(x) with y:



    swap x and y:



    Now, solve for y.

    They are easy to graph with a calculator or graphing utility.

    Here is a link to a wonderful FREE graphing utility:

    www.padowan.dk

    I do not know what Df, Rf, and so forth means.
  • Apr 7, 2011, 04:35 PM
    Mandeep100
    Galactus, I need to tell you something

    2. Consider the following function f(x) = -2 sqrt (-x + 4) - 3
    a) find the equation of the inverse function and graph f(x) and its inverse on a grid
    b) find Df
    Find D f^-1
    Rf
    R f^-1
    Those are domain and range can you please show me the full work I've been having a lot of trouble on this thanks
  • Apr 8, 2011, 07:52 AM
    Unknown008

    Can you draw the graph of f(x) ?

    The domain is the horizontal interval of a function.

    Let's say that I had for

    Then, for

    When you draw f and f^-1, you'll see that:

    The domain of f will lie between 0 and infinity. That is looking on the horizontal axis, f starts at zero and never ends.

    Similarly, the domain of f^-1 will be between 0 and infinity.

    The range of f is the vertical interval. Looking on the y axis, f starts at 0 and rises to infinity. The range is thus 0 to infinity. Same thing for f^-1.

    Now, can you deduce the range and domain of the functions in your problem?

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