# Making an equations using 2 functions?

• Oct 21st 2010, 06:33 AM
Mathmen
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
• Oct 21st 2010, 09:06 AM
Mathmen
is there anyone who knows i'm quite stuck here =/
• Oct 22nd 2010, 04:46 AM
Mathmen
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
• Oct 22nd 2010, 07:27 AM
Mathmen