# Having major issues with this problem - can someone get me started?

• Jun 9th 2012, 09:00 PM
kirshchereza
Having major issues with this problem - can someone get me started?
"The relationship between the load on a reel, L (kilotons) per metre (L kNm-1) and the reel diameter, x meters, is modelled by a graph consisting of two parabolic arcs, AB and BC

Picture of graph with L on the y-axis and x(meters) on the x axis with a parabola with points in order of A,D,E,F,B and C on the parabola.

Arc AB is part of the parabola L=px^2 +qx+r. Points D(0.1, 2.025), E(0.2,2.9) and F(0.3, 3.425) lie on the arc AB. Set up a system of three simultaneous equations relating to p, q and r. DO NOT SOLVE EQUATIONS.

Can anyone give me any help with this without the graph?

Thank you so much!
• Jun 10th 2012, 04:44 AM
skeeter
Re: Having major issues with this problem - can someone get me started?
if three points $(x_1,y_1)$ , $(x_2,y_2)$ , $(x_3,y_3)$ lie on the parabola $y = px^2 + qx + r$ , then ...

$y_1 = px_1^2 + qx_1 + r$

$y_2 = px_2^2 + qx_2 + r$

$y_3 = px_3^2 + qx_3 + r$