Given
→r1=(^i+2^j−4^k)+α(2^i+3^j+6^k)→r2=(^3i+3^j−5^k)+μ(2^i+3^j+6^k)
→r1=→a+λ→b
→r2=→c+λ→d
Distance between them is projection of →a−→c along the line perpendicular to both of them
Line DC's perpendicular to both →r1,→r2 is →b×→d|→b×→d|
Distance =(→a−→c)→b×→d|→b×→d|
=[→a−→c→b→d]|→b×→d|
But given lines are parallel lines
Let P be foot of perpendicular from →a on →r2
→a−→r2 is perpendicular to →b
(2μ+2,3μ+1,6μ−1) is perpendicular to (2,3,6)
(2)(2μ+2)+(3)(3μ+1)+(6)(6μ−1)=0
49μ=−1
μ=−149
2μ+2=9649
3μ+1=4649
6μ−1=−5549
Distance =|→a−→r2|=√962+462+55249=2.45