Question

Find the principal value of cos^–1x, for x = `sqrt(3)/2`.

Answer 1

If `cos^-1 (sqrt(3)/2)` = θ, then cos θ = `sqrt(3)/2`

Since we are considering principal branch, θ ∈ [0, π].

Also, since `sqrt(3)/2` > 0, θ being in he first quadrant

Hence `cos^-1 (sqrt(3)/2) = pi/6`