A line makes angles α,β,γ with the co-ordinate axis. If α+β=90°, then γ=
0°
90°
180°
None of these
Finding the value of
Since it is given that the line makes the angles α,β,γ with the coordinate axes,
cos2α+cos2β+cos2γ=1cos2α+cos2(90-α)+cos2γ=1(∵α+β=90)cos2α+sin2α+cos2γ=11+cos2γ=1cos2γ=0cosγ=0γ=90
Hence, the correct answer is option (B).
A line makes angles α, β and y with the positive directions of X-axis, Y-axis and Z-axis, respectively, then the directions cosines of the line are: