If a line makes angles α,β and γ with the coordinates axes, then cos2α+cos2β+cos2γ is
-1
-2
2
-3
Explanation for the correct option:
Find the value of given expression:
Given, The line makes angles α,β and γ with coordinate axis
∴l2+m2+n2=1
⇒cos2α+cos2β+cos2γ=1 ….(1)
Now,
cos2α+cos2β+cos2γ=2cos2α-1+2cos2β-1+2cos2γ-1=2cos2α+cos2β+cos2γ-3=21-3=-1
Hence, Option ‘A’ is Correct.