Verify by substitution that a given function is a solution of a given diff eq 1. y' = 3x2, y = x3+15 2. y" = -4y, y = sin(2x), y = cos(2x) 3. y' =, y = xlnx - x+C 4. y' = y+2e , y = ex -ex Solve the initial value problems 1. y' = 2x + 3, y(1) = 2 2. y'= 1 x2, y(1) = 5 3. y'= 10 x2+1 y(0) = 0