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#151 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 02:10:42

It does not, we just went from there. But so far no one has proved it is possible with n quadratics.

Thats why I am asking.

It seems to me that If there are 4 quad. you can define the 2 interesection points.

Similarly, if the polynomials were of degree 3,  6 polynomials of 3 degree might be needed...and so on...

But I am not sure

#152 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 02:03:35

bobbym wrote

Want to use post #9 and I will provide the two more quadratics since I know what A and B is?

What do you mean exactly?

#153 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 02:01:28

anonimnystefy

I think so.

I have the same opinion.

#154 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 01:51:23

anonimnystefy wrote:

I need a of four quadratics.

So, if you have 4 quadratics plus a point of each of them you can solve it? i.e you can find x0...y1?

#155 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 01:47:31

Ok. You are right. But I am confused with the equation of defining a2.

In equation of a2 only the 4 variables x0 x1 y0 y1 exist.

And
if I have four equations for a2 (I do not know the 4 polynomials, only that they have the same 2 inters. points x0 y0 x1 y1 (unknowns),

I know

each polynomial's  leading coef. i.e. a2

and one point of each of the polynomials.

Then from the set of 4 equations of a2, x0..y1 can be defined?

#156 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 01:37:52

x0 x1 y0 y1 are the same intersection points. the other one for each polynomial will be the known point.

#157 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 01:20:40

a2=2=   (7+    (y0-  ( (y1-y0) / (x1-x0))*(1-x1)))/ ( (1-x1)*(1-x0)

If i use this equation for a2, which unknons does it introduce?

#159 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 01:12:06

bobbym wrote:

Where is (2,6) and (8,2) coming from?

Consider that there are two more polynomials passing from the intersection points illustrated in your figure and I know their leading coefficient and one point form each of them i.e. 2,6 8,2.

#160 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 01:06:40

a2=2=   (7+    (y0-  ( (y1-y0) / (x1-x0))*(1-x1)))/ ( (1-x1)*(1-x0)


a2=-3=  (1+ (y0- (( y1-y0)/(x1-x0))*(2-x1))/ (2-x0)*(2-x1)

a2=8=  (6+ (y0- (( y1-y0)/(x1-x0))*(2-x1))/ (2-x0)*(2-x1)                          polynomial with a2=8 and a point 2,6

a2=11=  (12+ (y0- (( y1-y0)/(x1-x0))*(8-x1))/ (8-x0)*(8-x1)                     polynomial with a2=11 and a point 8,2

I can not solve this system of equations?

#161 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 00:55:03

To have a chance at getting those 4 as a number I need 4 equations.

So If you have at your disposal two more polynomials passing from the same intersection points you were able to define x0,y1?

#162 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 00:46:32

So, you mean that If I had 4 equations a2=.... I wouldn t be able to define x0,,y1?

#163 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 00:44:01

It seems that I used wrong a2 but the idea is still the same.

#164 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 00:40:48

Ok...What I am thinking is:

a2=2=   (7+    (y0-  ( (y1-y0) / (x1-x0))*(1-x1)))/ ( (1-x1)*(1-x0)
similarly for the second polynomial

a2=-3=  (1+ (y0- (( y1-y0)/(x1-x0))*(2-x1))/ (2-x0)*(2-x1)

If i had more polynomials could i find the x0 x1 y0 y1?

#165 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 00:23:32

Consider only coefficient a2.

The only unknowns are x0 x1 y0 y1.

If I have the coef.  a2 of four other polynomials could I determine the x0 x1 y0 y1?

I might be cinfused...

#166 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-20 00:03:03

Ok, That's right.

Let’ s use Newton Interpolation method to construct the known leading coefficient of the quadratic.

a_(2_known )=(y_known-(y_0+(y_1-y_(0  ))/(x_1-x_0 )(x_known-x_1))/((x_known-x_1)(x_known-x_0))

If I use the previous Equation for 4 quadratics, is it possible to define x0 x1 y0  y1  ?

P.S. How can I write efficiently the formulas??

#167 Re: Help Me ! » Define the intersection points of polynomials » 2013-06-19 23:45:05

Hmmm.Thats the problem. I know the leading coefficient and one point  from each of the polynomials.

But I m thinking that if I know the leading coef. and one point  from four polynomials

I might be able to find a set of 4 equations to define the four variables x0 x1 y0 y1.

Is ti possible?

#168 Help Me ! » Define the intersection points of polynomials » 2013-06-19 23:14:04

Herc11
Replies: 353

I am facing the following problem.

Let’s consider 2 points that are not known

I know that from these 2 unknown points

For each of these polynomials I know one point


Is it possible to find the intersection points (i.e. the 2 unknown points) of the aforementioned polynomials?

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