DIFFERENTIAL EQUATIONS PRACTICE PROBLEMS: ANSWERS
mathserver.neu.edu › ~bridger › U343DIFFERENTIAL EQUATIONS PRACTICE PROBLEMS: ANSWERS 1. Find the solution of y0 +2xy= x,withy(0) = −2. This is a linear equation. The integrating factor is e R 2xdx= ex2. Multiplying through by this, we get y0ex2 +2xex2y = xex2 (ex2y)0 = xex2 ex2y = R xex2dx= 1 2 ex2 +C y = 1 2 +Ce−x2. Putting in the initial condition gives C= −5/2,soy= 1 2 − 5 2 e=x2. 2.