Suppose that a fluid flow has the velocity field v x y Sket
     Suppose that a fluid flow has the velocity field v = (x, -y).  Sketch the vector field v at 8 equally spaced points on the unit circle  Suppose that a fluid particle is at (1, 1) when time t = 1. What is its location when t = 2?  Sketch flow lines of the fluid flow. That is, a family of lines on the xy-planes that indicate the path of the fluid particles. 
  
  Solution
The answer of the following question is as follows .
The location where the value of t=2 is (4,2)

