Definition of rotation of axes:
\The general second-degree equation
can be
written as
by rotating the axes by an angle
,
where
,
and
.
The equation is
.
Compare the equation
with general equation.
The values of
, and
.

Substitute
in
and
.
Consider
.

Consider
.

Substitute
and
in the equation
.

The rotated equation is
.
Graph :
\(1) Draw the coordinate plane.
\(2) Draw the rotated coordinate plane.
\(3) Graph the equation
.
The rotated equation is
.
Graph of equation
with rotated axis.