Find the shortest distance between the lines and .

Let the two lines be l1 and l2.


So, and


We need to find the shortest distance between l1 and l2.


Recall the shortest distance between the lines: and is given by



Here, (x1, y1, z1) = (2, 5, 0) and (x2, y2, z2) = (0, –1, 1)


Also (a1, b1, c1) = (–1, 2, 3) and (a2, b2, c2) = (2, –1, 2)


We will evaluate the numerator first.


Let




N = (–2)[(2)(2) – (–1)(3)] – (–6)[(–1)(2) – (2)(3)] + (1)[(–1)(–1) – (2)(2)]


N = –2(4 + 3) + 6(–2 – 6) + (1 – 4)


N = –14 – 48 – 3


N = –65


Now, we will evaluate the denominator.


Let


b1c2 – b2c1 = (2)(2) – (–1)(3) = 4 – (–3) = 7


c1a2 – c2a1 = (3)(2) – (2)(–1) = 6 – (–2) = 8


a1b2 – a2b1 = (–1)(–1) – (2)(2) = 1 – 4 = –3





So, shortest distance =


Thus, the required shortest distance is units.


1