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Math Help - Need some function help.

  1. #1
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    Need some function help.

    Hey guys,

    I have a math assignment due on Monday, and I'm having difficulties understanding what two of the questions are asking.

    1) Calulcate f(x+h) when:
    a) f(x)=x^2
    ...
    In each case, write down the corresponding expression for f(x+h) - f(x). Replace the right side of the equation with x+h for each instance.
    My instructor didn't really go over questions like these all that much in class, so I'm not entirely sure what the question is asking. I have a similar issue with this question:

    2) If f(x)=1/(1-x)^2, find f(x/t).
    Is this just asking to find (1/(1-x)^2)/t?

    Any help would be greatly appreciated!
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  2. #2
    A Plied Mathematician
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    Is this assignment for a grade?
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  3. #3
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    Quote Originally Posted by Eternalspirit View Post
    Is this just asking to find (1/(1-x)^2)/t?
    If f(x)=x^2 then f(x+h)=(x+h)^2=~? (EXPAND)

    If f(x)=\frac{1}{(1+x)^2} then f\left(\frac{x}{t}\right)=\frac{1}{\left(1+\frac{x  }{t}\right)^2}
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  4. #4
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    Quote Originally Posted by Ackbeet View Post
    Is this assignment for a grade?
    Yeah.. I'm not looking for an answer, just what the questions are asking in a clearer way.
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  5. #5
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    Quote Originally Posted by Plato View Post
    If f(x)=x^2 then f(x+h)=(x+h)^2=~? (EXPAND)

    If f(x)=\frac{1}{(1+x)^2} then f\left(\frac{x}{t}\right)=\frac{1}{\left(1+\frac{x  }{t}\right)^2}
    For the first part.. I got that far as well, but what do I do about the second part of the question, asking for f(x+h)-f(x)?

    Also, thanks for point 2! That's initially what I was leaning towards.
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  6. #6
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    Can you expand and simplify [(x+h)^2]-[(x^2)]~?
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  7. #7
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    Quote Originally Posted by Plato View Post
    Can you expand and simplify [(x+h)^2]-[(x^2)]~?
    Is that all it's asking?

    (x+h)^2 = x^2+h^2+2xh

    x^2+h^2+2xh - x^2 = h^2+2xh.. which is exactly what I thought it was at first, but was unclear.
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  8. #8
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    I think I got it. Thanks guys!
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  9. #9
    A Plied Mathematician
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    Next time, please do not post problems that count towards your final grade. Hint: take a problem that does count toward your final grade, and tweak it enough so that it's definitely not the same problem, but still retains the essential features of the problem you're trying to solve.

    Thank you.
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