Q. 295.0( 1 Vote )

# Write the vector equations of the following lines and hence determine the distance between them:

Answer :

We need to find the vector equations of the given lines and also determine the distance between them.

Let line be,

So, points (x, y, z) are on L_{1}.

Let us find (x, y, z).

⇒ (x – 1) = 2λ, (y – 2) = 3λ, (z + 4) = 6λ

⇒ x = 2λ + 1, y = 3λ + 2, z = 6λ – 4

So, the points on line L_{1} comes out be (2λ + 1, 3λ + 2, 6λ – 4).

And the other line be,

So, points (x, y, z) are on L_{2}.

Let us find (x, y, z).

⇒ (x – 3) = 4μ, (y – 3) = 6μ, (z + 5) = 12μ

⇒ x = 4μ + 3, y = 6μ + 3, z = 12μ – 5

So, the points on line L_{2} comes out to be (4μ + 3, 6μ + 3, 12μ – 5).

Let us find the vector equation of line L_{1} using the points (2λ + 1, 3λ + 2, 6λ – 4):

Rearranging them,

…(i)

Now, let us find the vector equation of line L_{2} usinf the points (4μ + 3, 6μ + 3, 12μ – 5):

Rearranging them,

…(ii)

We have got the vector equations namely, and .

Let us find the distance between the lines.

From (i),

Let,

From (ii),

Let,

Distance between the vector equations of the two given lines when is given by,

So, using the values of and , we get

Now, solving for . We get

Taking mod on both sides,

Let us find the mod of .

So,

Thus, vector equation of line L_{1} is and line L_{2} is and the distance between the lines is .

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Find the vector and Cartesian equations of the line through the point (1, 2, -4) and perpendicular to the two lines.

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Mathematics - Board PapersWrite the vector equations of the following lines and hence determine the distance between them:

Mathematics - Board Papers