Given: A vector is equally inclined to the x-axis, y-axis and z-axis respectively. Therefore, α = β = γ As we know that, cos2 α + cos2 β + cos2 γ = 1 ⇒ cos2 α + cos2 α + cos2 α = 1 ⇒ 3 cos2 α = 1 ⇒ cos2 α = 1/3 ∴ cos α =±(1∕√3) Therefore, cos α = cos β = cos γ =±(1∕√3) So, l = m = n =±(1∕√3) Now, Direction cosine of the vector is <