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Math Help - Brief Calculus Help

  1. #1
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    Brief Calculus Help

    Hello,
    I am new here. I am taking an online calculus course and I am having trouble answering these two questions:

    Find and simplify.

    f (x)=7x-1

    A) f (x+h)-f (x) /h Bold is on top of h


    f (x)=4-x^2

    A) f (x+h)-f (x) /h Bold is on top of h

    B) f (x+h)-f (x)

    Thank You
    Last edited by bwirth; August 29th 2010 at 04:51 PM.
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  2. #2
    Behold, the power of SARDINES!
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    Quote Originally Posted by bwirth View Post
    Hello,
    I am new here. I am taking an online calculus course and I am having trouble answering these two questions:

    Find and simplify.

    f (x)=7x-1

    A) f (x+h)-f (x) /4 Bold is on top of 4


    f (x)=4-x^2

    A) f (x+h)-f (x) /4 Bold is on top of 4

    B) f (x+h)-f (x)

    Thank You
    Function notation means you evaluate the function f at the value given

    \displaystyle \frac{[f(x+h)-f(x)}{4}=\frac{[7(x+h)-1]-(7x-1)}{4}
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  3. #3
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    Here's a kick start.

    \displaystyle \frac{f(x+h)-f(x)}{4} = \frac{(7(x+h)-1)-(7x-1)}{4}= \frac{7x+7h-1-7x+1}{4}
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  4. #4
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    Thanks Pickslides,

    That helps me understand how to do that type of problem. I seem to be doing something wrong with the ^2 problems though. By the way, I changed the equation above, they are over h not 4.
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  5. #5
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    I had a feeling h would be in the denominator

    \displaystyle \frac{f(x+h)-f(x)}{h} = \frac{(4-(x+h)^2-1)-(4-x^2)}{h}= \frac{4-(x^2+2xh+h^2)-4+x^2}{h}= \displaystyle\frac{4-x^2-2xh-h^2-4+x^2}{h}=  \frac{-2xh-h^2}{h}=  \frac{h(-2x-h)}{h} = -2x-h
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  6. #6
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    Quote Originally Posted by pickslides View Post
    I had a feeling h would be in the denominator

    \displaystyle \frac{f(x+h)-f(x)}{h} = \frac{(4-(x+h)^2-1)-(4-x^2)}{h}= \frac{4-(x^2+2xh+h^2)-4+x^2}{h}= \displaystyle\frac{4-x^2-2xh-h^2-4+x^2}{h}=  \frac{-2xh-h^2}{h}=  \frac{h(-2x-h)}{h} = -2x-h
    Your the man Pickslides. That helped me figure out the rest of my homework problems. I really wish these online classes followed along with a book. Thanks again!
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