Engineering Board Exam Reviewer · Orthogonal Trajectories · medium
Find the orthogonal trajectories of the family of lines y=Cx.
- x2+y2=C
- y2-x2=C
- xy=C
- y=-x+C
Answer
A. x2+y2=C
Solution
Eliminating C: dy/dx=y/x. The orthogonal family satisfies dy/dx=-x/y y,dy=-x,dx x2+y2=C.