Finding the Angle of Rotation
Key Questions
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xy term in the equation of a conic section indicates, there is a rotation of axes
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Answer:
Use a formula and solve for angle of rotation =
thetaθ Explanation:
For the formulas I use, we must put the equation in the form:
Ax^2 +Bxy+Cy^2 +Dx + Ey +F =0Ax2+Bxy+Cy2+Dx+Ey+F=0 Use
cot2theta = (A-C)/Bcot2θ=A−CB ortan2theta = B/(A-C)tan2θ=BA−C .Solve for
thetaθ .(The
D, E, " and " FD,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:
IfA = CA=C , thencot2theta = 0cot2θ=0 , sotheta = pi/4θ=π4