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Math Help - Checking Tangent

  1. #1
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    Checking Tangent

    Find the slope and the equation of the tangent line to the function f(x)=x^2+3x+2 at x=1.

    My answer: 3
    1x+3x+2=6x
    f(x) -f(1)/x(-1)=3
    Is that right??
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  2. #2
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    Quote Originally Posted by batman123
    Find the slope and the equation of the tangent line to the function f(x)=x^2+3x+2 at x=1.

    My answer: 3
    1x+3x+2=6x
    f(x) -f(1)/x(-1)=3
    Is that right??
    Slope is the derivative evaluated at x=1
    thus,
    f'(x)=2x+3
    thus,
    f'(1)=2(1)+3=5
    Thus, slope is 5.
    -------
    To find equation use the formula,
    y-y_0=m(x-x_0)
    where (x_0,y_0) is a point.
    Notice if x_0=1 then, y_0=f(1)=6
    Thus,
    y-6=5(x-1)
    Solve for y thus,
    y=5x+1
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  3. #3
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    Thanks

    thank you I see what I did wrong.
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