1. Find an equation of the form H (x, y ) = c satised by solutions of the given systems.
(a)
dx
= 2x2 y 3x2 4y
dt
dy
= 2xy 2 + 6xy.
dt
Answer: x2 y 2 3x2 y 2y 2 = c.
(b)
dx
= x
dt
dy
= 2y.
dt
Answer: yx2 = c.
2. Page 231: 3, 20, 22
3. If y1 and y2 are fun