The equation of the passing through (1,0,3) and having direction cosines  a,b,12 in Symmetric form is  x−1a=yb=z−312 then a2+b2 is

The Equation of the line passing through the point (x1,y1,z1) and having direction ratios ⟨a,b,c⟩ is x−x1a=y−y1b=z−z1cThe equation of the line passing through the point (1,0,3) and having direction cosines  a,b,12 is x−1a=y−0b=z−312since a,b,12 are direction cosines of the line, then a2+b2+14=1⇒a2+b2=34