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.