Determine whether the following pair of lines intersect or not :

and z = 2

Given: - Two lines equation: and ; z = 3


We have,



x = 2λ + 1, y = 3λ – 1 and z = λ


So, the coordinates of a general point on this line are


(2λ + 1, 3λ – 1, λ)


The equation of the 2nd line is



x = 5μ + 1, y = μ + 2 and z = 3


So, the coordinates of a general point on this line are


(5μ + 1, μ + 2, 3)


If the lines intersect, then they must have a common point.


Therefore for some value of λ and μ, we have


2λ + 1 = 5μ + 1 , 3λ – 1 = μ + 2, and λ = 3


2λ – 5μ = 0 ……(i)


3λ – μ = 3 ……(ii)


and λ = 3 ……(iii)


putting the value of λ from eq iii in eq ii, we get


3λ – μ = 3


3(3) – μ = 3


μ = 6


As we can see by putting the value of λ and μ in eq i, that it does not satisfy the equation.


Check


2λ – 5μ = 0


2(3) – 5(6) = 0


– 24 = 0


LHS≠RHS; Hence intersection point exists or line does not intersects.


6