Question

If a line makes angles 90∘,135∘,45∘ with the x, y and z axes respectively, find its direction cosines.

Answer 1

Answer:

Direction cosines [cos 90, cos 135,cos45]

=[0,-1/v2, 1/v2]

Answer 2

Answer:

The direction cosines of the lineare 0, -1/√2, 1/√2

Step-by-step explanation:

Let the direction cosines of the line be

l, m and n.

Here let

α = 90°,

β = 135°

and γ = 45°

So,

l = cos α,

m = cos β and

n = cos γ

So direction cosines are,

l = cos 90° = 0

m = cos 135°

= cos (180° -45°)

= -cos 45°

=-1/√2

n = cos 45°

=1/√2

∴The direction cosines of the lineare 0, -1/√2, 1/√2