\
Step 1 :
\Rotation formula :
\If the x and y-axes are rotated through an angle , the coordinates
of a point P relative to the xy -plane and the coordinates
of the same point relative to the new x and y-axis and are related by the formulas
and
.
The general form is
The angle is .
Step 2 :
\The equation is .
Compare with
and
.
The angle is .
Substitute and
in
Step 3 :
\Rotation of x - axis :
\.
Substitute in above equation.
Rotation of y - axis :
\.
Substitute in above equation.
The rotation formulas are and
..
Step 4 :
\Substitute and
in
.
Divide each side 12.
\The above equation is an ellipse.
\\
\
Step 6 :
\\
The graph of the function .
Solution :
\The equation of an ellipse is
The graph of the function .