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+--- Thread: Solving rotation of conics on the Prime? Is there perhaps a better way? (/thread-4688.html)
Solving rotation of conics on the Prime? Is there perhaps a better way? - pwarmuth - 09-09-2015 04:11 PM
I would like to know if there is a better way to do this on the HP prime. Is there a built in function or something I can use to simplify this process, besides writing a custom program? It's so tedious.
Transform the equation in x and y into an equation in X and Y (without an XY-term) by rotating the x- and y-axes by the indicated angle. I am using the Prime to verify my answers.
Problem: y^2 -sqrt(3)*x*y + 3 = 0 where theta is 30 degrees.
For reference: x=x, y=y, a=X', b=Y' and c=theta
[CAS]
[set degree mode]
x:=a*cos(c)-b*sin(c)
y:=a*sin(c)+b*cos(c)
c:=30
then use the stored variables to evaluate the equation that I'm working with.
y^2-sqrt(3)*x*y+3=0
That input simplifies to
[(-a)^2+3b^2+6]/2=0
Takes a little more manual transformation to get it into the standard form of a hyperbola, and I arrive then at the correct answer:
[(a^2)/6] -[(b^2)/2] = 1 where a = x and b=y.
RE: Solving rotation of conics on the Prime? Is there perhaps a better way? - math7 - 01-17-2018 03:40 AM
definitely the HP Prime needs a conic application, if I could program to the required level I would but I do not have that knowledge...
RE: Solving rotation of conics on the Prime? Is there perhaps a better way? - parisse - 01-19-2018 10:13 AM
Giac has a command to find the center, axis of a conic and return the reduced equations: it's reduced_conic. Maybe it's in the public beta.
RE: Solving rotation of conics on the Prime? Is there perhaps a better way? - salvomic - 01-19-2018 10:16 AM
(01-19-2018 10:13 AM)parisse Wrote: Giac has a command to find the center, axis of a conic and return the reduced equations: it's reduced_conic. Maybe it's in the public beta.
yes, it is already in the beta v3:
Code:
reduced_conic(Expr,[Vector])Salvo