If m=2, PQ is perpendicular to the X axis, and the inclination =π/2.

If m≠2, then K exists.

K = (1+3)/(2m) = 4/(2m)

If m>2

Then k < 0

Because the tilt angle is greater than or equal to 0 and less than π.

So the tilt angle =π+arctan[4/(2-m)]

If m<2

So k>0

So the tilt angle =arctan[4/(2-m)]