The solution of the differential equation (1 + y2) dx = (tan-1((y) - x)dy is
None of the above
B.
The differential equation of the family of circles touching the y-axis at the origin is
xy' - 2y = 0
y'' - 4y' + 4y = 0
2xyy' + x2 = y2
2yy' + y2 = x2