Question -
Answer -
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 line are 0, -1/√2, 1/√2