The equation is
.
Multiply each side by
.

Differentiate on both sides with respective to
.

The R.H.S of the equation is
, because the derivative of the constant is
.
Consider the L.H.S :
Use product rule :
.

Replace
with
.


Apply cross multiplication.
\
Now integrate on both sides.
\
Therefore,
.
The function is
.
(1) Draw the coordinate plane.
\(2) Graph the function
for several values of
.
The curves
and
represents the orthogonal trajectories.
The parabolas represent the given family of curves.
\Graph :
\