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Math Help - Making an equations using 2 functions?

  1. #1
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    Making an equations using 2 functions?

    Hi there i'm having some problems with this one can't really figure it out couldn't attach the graphs so i wrote where they hit the y and x axis instead the first is a curve and the other is linear

    Make the function y = x * f(g(x)) where the function y=f(g(x)) is defined by two graphs. One of the graphs y = f(u) (the graf is a curve that x-axis on -1 and the y-axis on just around 0.25 and 3.75) has the tangents where u = 1 and u = 3 and the other graph is named u = g(x) (the graf is linear and hits the y-axis on 2.5). The graph for the equations y = x* f(g(x)) has the tangent x = 1. Define the equation for the tangent

    /Mathmen
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  2. #2
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    is there anyone who knows i'm quite stuck here =/
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  3. #3
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    am i on the right path

    this is as far as i have come =/

    y = f(u)
    u = g(x)

    if we incorporate u= g(x) in to y = f(u) we get y = f(g(x)) which is one step closer to y= x * f(g(x)) but from here i can't really use a valid formula that allows me to go any further. I was thinking y2 - y1 = k(x2 - x1) or also y = kx+b
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  4. #4
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    Is this the right answer?

    After sitting with the question for a couple of hours a came to this answer, i would really appreciate if anyone can tell me if i made any type of misstake during the process because i'm quite confused if it should actually become y2 = x + f(g(1)) or y2 = x* f(g(1))


    Y2 y 1 = k(x2 x1)
    Y2 f(g(1)) = f(g(1)) * g(1) (x2 -1)
    y2 f(g(1)) = f(g(1)) * g(1) * x - f(g(1)) * g(1)
    Y2 = f(g(1)) * g(1) * x - f(g(1)) * g(1) + f(g(1))
    y2 = x* f(g(1))

    Thanks!
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