Finding the Angle of Rotation
Key Questions

xy term in the equation of a conic section indicates, there is a rotation of axes

Answer:
Use a formula and solve for angle of rotation =
#theta# Explanation:
For the formulas I use, we must put the equation in the form:
#Ax^2 +Bxy+Cy^2 +Dx + Ey +F =0# Use
#cot2theta = (AC)/B# or#tan2theta = B/(AC)# .Solve for
#theta# .(The
#D, E, " and " F# are not used in the formulas.)Your textbook/teacher may prefer a different form, which would lead to different formulas.
Note/Example:
If#A = C# , then#cot2theta = 0# , so#theta = pi/4#