Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: geometry help
Replies: 8   Last Post: Apr 26, 2014 11:56 AM

 Messages: [ Previous | Next ]
 Narasimham Posts: 359 Registered: 9/16/06
Re: geometry help
Posted: Apr 23, 2014 8:00 PM

Let the 4 points be: (0,2), (1,3), (3,3.6), (5,0.2).

y = d + c x + Sqrt [b + a x ] is the equation of downward parabola. By changing sign before radical sign you obtain upward parabola.

Mathematica program is:

y[a_,b_,c_,d_,x_]= Sqrt[a x + b ]+ c x +d
NSolve[{2.-y[a,b,c,d,0]==0, 3.-y[a,b,c,d,1]==0, 3.6 -y[a,b,c,d,3]==0, 0.2-y[a,b,c,d,5] == 0},{a,b,c,d}]

{{a->-355.769,b->2176.17,c->4.98328,d->-44.6495}}

Plot[Sqrt[ -355.76915062347183` x + 2176.1738248547367` ] + 4.983277684410211` x -44.64947829134573` , { x, -1, 6},PlotStyle-> {Red,Thick}, GridLines-> Automatic]

The equation of parabola is a special case of general conics.

HTH
Narasimham

Date Subject Author
4/23/14 kelvin_m
4/23/14 Narasimham
4/24/14 Peter Scales
4/24/14 kelvin_m
4/24/14 kelvin_m
4/24/14 Narasimham
4/25/14 Peter Scales
4/26/14 Narasimham
4/26/14 Peter Scales