Question

If a line makes angles 90°, 135°, 45° with x, y and z-axis respectively then which of the following will be its direction cosine.

विकल्प

• `(0, - 1/sqrt(2), 1/sqrt(2))`

• `(1/sqrt(2), 0, -1/sqrt(2))`

• `(1/sqrt(2), -1/sqrt(2), 0)`

• `(0, 1/2, 1)`

Answer 1

`(0, - 1/sqrt(2), 1/sqrt(2))`

Explanation:

Direction angles are 90°, 135°, 45°

∴ Direction consine are `l` = cos 90° = 0, m = cos 135° = `1/2` n = cos 45° = `1/sqrt(2)`

Hence direction cosines `0, - 1/sqrt(2), 1/sqrt(2)`