Question

The direction ratios of the line 3x + 1 = 6y – 2 = 1 – z are ______.

Options

• 2, 1, 6

• 2, 1, – 6

• 2, – 1, 6

• – 2, 1, 6

Answer 1

The direction ratios of the line 3x + 1 = 6y – 2 = 1 – z are 2, 1, – 6.

Explanation:

`(3x + 1)/1 = (6y - 2)/1 = (1 - z)/1`

∴ `(x + 1/3)/(1/3) = (y - 1/3)/(1/6) = (z - 1)/-1`

These equations are of the form

`(x - x_1)/a = (y - y_1)/b = (z - z_1)/c`

∴ Direction ratios of the line are

`1/3, 1/6, -1`

i.e. 2, 1, –6