The equation is
.
Diffrentiate with respective to
.

Replace
with
.

Consider
.
Seperate the variables.
\
Now integrate on both sides.
\
Where
is an integration constant.
.
Substiute
.
.
From the logarthamic property :
and 


(1). Draw the coordinate plane.
\(2). Graph the function
for several values of
.
The circles represents the given family of curves.
\The curves represents the orthoganal trajectories.
\Graph :
\