Engineering Board Exam Reviewer · Exact Differential Equations · easy

For M=2xy, which choice of N makes M,dx+N,dy=0 exact?

  1. N=y2
  2. N=x2
  3. N=2x
  4. N=xy

Answer

B. N=x2

Solution

Exactness requires N/ x= M/ y=2x, which holds for N=x2.

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