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Math Help - composites

  1. #1
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    composites

    Find (f o g) at x = 4 if f(u)=u^3 - 5 and u= g(x)= 3(x^(1/2))

    I got (f o g) = 40.5(x^1/2)
    Can someone tell me if I did it right?
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  2. #2
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    Quote Originally Posted by h4hv4hd4si4n View Post
    Find (f o g) at x = 4 if f(u)=u^3 - 5 and u= g(x)= 3(x^(1/2))

    I got (f o g) = 40.5(x^1/2)
    Can someone tell me if I did it right?
    What you mean by (f o g)?
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  3. #3
    Senior Member MacstersUndead's Avatar
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    That is the correct answer.
    (f o g) = (3(x^1/2))^3 - 5 = 27x^3/2 - 5
    (f o g) = (81/2) x^1/2

    @Mush: The derivative of the function g composed into the function of f.
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  4. #4
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    Quote Originally Posted by MacstersUndead View Post
    That is the correct answer.
    (f o g) = (3(x^1/2))^3 - 5 = 27x^3/2 - 5
    (f o g) = (81/2) x^1/2

    @Mush: The derivative of the function g composed into the function of f.
    Ah. Yes, then the OP is correct. Remember to implement the condition that x=4.
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  5. #5
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    thanks for checking it out for me
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