How to find 3D point on the 3D line with given distance and from given 3D point

[gbalajimecse]

Hi

how to find 3D point(lie on line) on the 3D line with given distance and from given 3D point(this is also lie in line) where the given line equation

Please explain the derivation

 

[zhentil]

I would parametrize the line and write down the distance equation as a function of t.