Find parametric equations of the line passing through the po
Find parametric equations of the line passing through the points (1,2,3) and (3,5,7) and calculate the shortest distance from the line to the origin.
Solution
The parametric equation of the line is:
t(1,2,3) + (1-t)(3,5,7) =
(t,2t,3t)+(3-3t , 5-5t , 7-7t) =
(3-2t , 5-3t , 7-4t)
To find the shortest distance we have:
d(t) = (3-2t-0)2 + (5-3t-0)2 + (7-4t-0)2
d\'(t) = -4(3-2t) - 6(5-3t) - 8(7-4t) = 0
-12+8t-30+18t-56+32t = 0
58t = 98
t = 98/58 = 49/29
So the shortest distance is:
d(49/29) = ((3-2*49/29)2 + (5-3*49/29)2 + (7-4*49/29)2) = (6/29) = 0.4549
