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Math Help - more Composition function

  1. #1
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    more Composition function

    Given f(x)= (square root) x+3, g(x)=x^2-9 and h(x)=1/x

    Determine a) f o g
    b) g o h
    c) f o g o h
    d) g o f o h
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  2. #2
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    Here are two examples. Use them to work your problems.
    h \circ f(x) = \frac{1}{{\sqrt {x + 3} }}\,\& \,f \circ h(x) = \sqrt {\frac{1}{x} + 3} <br />
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  3. #3
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    Quote Originally Posted by johett View Post
    Given f(x)= (square root) x+3, g(x)=x^2-9 and h(x)=1/x

    Determine a) f o g
    b) g o h
    c) f o g o h
    d) g o f o h
    For the first one, you simply plug in the function g for x in function f. B is the same process for different functions.

    C is a little trickier. What it is asking you to do is plug in the function h for x in function g. Once you get that, you then plug in function f into all x's in the g o h composite function. Then simplify. D is the same thing, but the functions are being plugged in in a different order.
    Last edited by mathgeek777; December 28th 2007 at 01:58 PM. Reason: Stuff out of order, fixed now :)
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  4. #4
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    Quote Originally Posted by mathgeek777 View Post
    For the first one, . B is the same process for different functions. you simply plug in the function f for x in function g
    C is a little trickier. What it is asking you to do is plug in the function g for x in function h. Once you get that, you then plug in function f into all x's in the g o h composite function. Then simplify. D is the same thing, but the functions are being plugged in in a different order.
    mathgeek777 you have it all backwards.
    Look at the examples that I gave.
    You should know that f \circ g(x) = f\left( {g(x)} \right)
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  5. #5
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    Quote Originally Posted by Plato View Post
    mathgeek777 you have it all backwards.
    Look at the examples that I gave.
    You should know that f \circ g(x) = f\left( {g(x)} \right)
    I've been off today so please forgive me. Today has not been the greatest day in the world for me.

    You are right, I'll go fix that right away.
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  6. #6
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    Can someone post the final answers so when I'm finish, I can check if I did it right. Thank you
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  7. #7
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    Quote Originally Posted by johett View Post
    Can someone post the final answers so when I'm finish
    Don't beg or bump.
    You post your answers and let us check to see that you have done something on your own.
    This is a help site not a homework done site.
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  8. #8
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    Quote Originally Posted by johett View Post
    Can someone post the final answers so when I'm finish, I can check if I did it right. Thank you
    Why don't you post your solution and we'll be happy to look at it.

    -Dan
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