Question

How to eliminate the xy term in

Ax^2 + Bxy + Cy^2 +Dx + Ey + F = 0

(B not 0, obviously)

by making a suitable rotation?

Answer 1

i was gonna say rotate it lol

Answer 2

determine the slope between your foci if its elliptic or hyperbolic

Answer 3

i never did learn the technical steps for it tho

Answer 4

Maybe I need to be more concrete:

19x^2 + 6xy + 11y^2 -40 = 0

What's the rotation to get rid of the xy?

Answer 5

the graph looks to indicate a rotation of 45 degrees

Answer 6

but how to determine that I cant say for sure

Answer 7

http://en.wikipedia.org/wiki/Rotation_of_axes