> > Thanks for taking a look at my post, but unless I have missed
> > something very obvious y should be quadratic, you seem to have lost
> > some astrices when you copied the equation.
Yes...see my comment above.
> > The values given were constructed in Geogebra and the answer should be
> > x = 4.4, y = 2.22 which I checked manually so I'm pretty sure it's
> > correct.
Yes, those are correct, and so is one of the other pair that I gave.
The problem is that the two pairs of solutions obtained from eq1 and
eq3 don't satisfy eq2. I wonder if that means you need solve eq1 and
eq2 or eq2 and eq3 to get the other correct answer that matches
yours...but master cannot do that now.
But if you can supply a good initial guess for the intersection,
nsolve can solve pairs of equations quickly:
The definitions:
>>> eq1
1 + y**2/(-a + e**2) - (e + x)**2/a
>>> eq3
1 + y**2/(-c + e**2) - (x - e)**2/c
>>> r1
{'a': (na2/2 - nc2/2)**2, 'c': (nd2/2 - nc2/2)**2, 'b': (nb2/2 -
nc2/2)**2, 'e': ne2/2}
>>> r2
{'na2': 5.1012506603354302, 'nb2': 1.8440254147031681, 'nc2':
2.3037501316409941, 'nd2': 0, 'ne2': 3}
>>> guess=dict(x=4.4,y=2.22)
The numerical forms (in terms of x and y):
>>> q1=eq1.subs(r1).subs(r2)
>>> q1
1 + 3.4071817491355*y**2 - 0.511116188808945*(3/2 + x)**2
>>> q3=eq3.subs(r1).subs(r2)
The solution:
(yours)
>>> nsolve([q1,q3],[x,y],[4.4,2.2])
matrix(
[['4.39999999999999'],
['2.22']])
(mine)
>>> nsolve([q1,q3],[x,y],[.2, -.4])
matrix(
[['0.249149607516349'],
['-0.406775010230429']])
Is there a reason you are solving these 3 equations rather than the
two general equations? e.g. as posted at
https://nrich.maths.org/discus/messages/117730/143478.html?1205141927
Also I see a web page addressing "Method for elimination of ambiguous
solutions in a hyperbolic positioning system" (http://
www.patentstorm.us/patents/5454720/description.html) so spurious
solutions is something that will need to be addressed (as you have
been doing).
--
You received this message because you are subscribed to the Google Groups
"sympy" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sympy?hl=en.
