Let O be the origin, and M and N be the points on the lines x-54= y-41= z-53 and x+812= y+25= z+119 respectively such that MN is the shortest distance between the given lines. Then OM ON is equal to .
Answer
9
Solution
M(4 +5, +4, 3 +5), N(12 -8, 5 -2, 9 -11)
MN=(12 -4 -13, 5 - -6, 9 -3 -16)
b1 b2= vmatrix i& j& k\\4&1&3\\12&5&9 vmatrix=-6 i+0 j+8 k
MN both lines ⇒ MN b1 b2 (-3, 0, 4)
y-component =0 =5 -6
MN=(11-8 , 0, 2-6 ); 11-8 -3= 2-6 4 =1, =-1
M(1, 3, 2), N(4, 3, -2)
OM ON=4+9-4=9
Answer: 9