Question

Hello I was just wondering if I have an ellipse given by the general equation;
ax^2+bxy+cy^2+dx+ey=f
What is the angle of inclination of the major axis to the x axis. (I have an answer in cartesian coords but I've been told its wrong)
Tan(phi)=b/(a-c)
Could someone please post the correct formula, I've been searching the internet but can't find it

Answer 1

is phi the angle of rotation?

Answer 2

tan(2*phi)=b/(a-c)

Answer 3

Yes thats it, thank you very much Must have taken it down wrong in the lecture Thanks :)

Answer 4

yw