[bigbadb1319]

Ex. 4A, Q1

Find dy/dx for each of the following, leaving your answer in terms of the parameter t;

g).
x=2t/1+t²
y=1-t²/1+t²

i don't know where i'm going wrong, i think its the simplification part! the answer is suppose to be: 2t/t²-1

thanx...

[Chewwy]

ah, anything but my own homework:

dy/dx = dy/dt * dt/dx

dx/dt = ((1+t^2)2 - 2t(2t))/(1+t^2)^2
dt/dx is inverse

dy/dt = ((1+t^2)(-2t) - (1-t^2)(2t))/(1+t^2)^2

dy/dx = ((1+t^2)(-2t) - (1-t^2)(2t))/(1+t^2)^2 * (1+t^2)^2/((1+t^2)2 - 2t(2t)) = ((1+t^2)(-2t) - (1-t^2)(2t))/((1+t^2)2 - 2t(2t)) = -4t/(2-2t^2) = 2t/t²-1

yeah baby.

[bigbadb1319]

thanx....