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CALCULUS HELP NEEDED!!!?

g(x) = (2x-3.5)/(2x-12.25)^2

find the concavity, inflection points, x and y intercept , relative maximum and minimum ,increasing decreasing?

please explain your work I really want to learn this.

cheers!

2 Answers

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  • cidyah
    Lv 7
    7 years ago
    Favorite Answer

    f(x) = (2x-3.5) /(2x-12.5)^2

    x-intercept: set y=0

    (2x-3.5) /(2x-12.5)^2 = 0

    2x=3.5

    x = 3.5/2 = 1.75

    x-intercept : (1.75,0)

    y-intercept: set x=0

    y= -3.5/-12.5^2

    y = -0.0224

    y-intercept : (0, -0.0224)

    f(x) = (2x-3.5) /(2x-12.5)^2

    f(x) = (2x-3.5)(2x-12.5)^(-2)

    f'(x) = (2) (2x-12.5)^(-2) + (2x-3.5) (-2)(2x-12.5)^(-3)(2)

    f'(x) = 2 / (2x-12.5)^2 - 4 (2x-3.5) / (2x-12.5)^3 = 0

    2(2x-12.5) / (2x-12.5)^3 - 4 (2x-3.5) / (2x-12.5)^3 = 0

    [2(2x-12.5) - 4(2x-3.5)] / (2x-12.5)^3 = 0

    [2(2x-12.5) - 4(2x-3.5)] = 0

    -4x-25+14 =0

    -4x = 11

    x= -2.75 is the critical point

    f'(x) = 2 / (2x-12.5)^2 - 4 (2x-3.5) / (2x-12.5)^3

    f'(x) = 2(2x-12.5)^(-2) - 4(2x-3.5)(2x-12.5)^(-3)

    f''(x) = (2)(-2)(2x-12.5)^(-3)(2) - 4(2)(2x-12.5)^(-3) - 4(2x-3.5)(-3)(2x-12.5)^(-4)(2)

    f''(x) = -8 / (2x-12.5)^3 - 8 /(2x-12.5)^3 +24 (2x-3.5) /(2x-12.5)^4

    f''(x) = -16 /(2x-3.5)^3 + 24 (2x-3.5) /(2x-12.5)^4

    f''(-2.75) = 0.0199 > 0, so f has a relative minimum at x=-2.75

    The minimum is f(-2.75) = -0.02777

    Consider the intervals (-∞, -2.75),(-2.75, ∞)

    choose any one point from each of the intervals.

    if f'(x) < 0 , f(x) is decreasing on that interval

    if f'(x) > 0 , f(x) is increasing on that interval

  • Anonymous
    7 years ago

    1. Read the Q

    2. Solve the Q

    3. ???

    4. Profit

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