The equation is
.
Differentiate on each side with respect to
.



.

Find orthogonal trajectory :
\
Apply cross multiplication.
\
.
Integrate on each side.
\
.
Integrate power rule:
.

The function is
.
(1) Draw the coordinate plane.
\(2) Graph the function
for several values of
.
Graph :
\
.
The curves represent the given family of curves.
\The ellicpse represent the orthogonal trajectories.
\Graph :
\
.