6* в корне11 *cos*( 3п/2 - arccos*( -1/2 ))

Question

6* в корне11 *cos*( 3п/2 - arccos*( -1/2 ))

Answer 1

6√11 · cos(3π/2 - arccos(-1/2)) = 6√11 · cos(3π/2 - 2π/3) = 6√11 · cos(5π/6) =
= 6√11 · cos(π - π/6) = 6√11 · (-cosπ/6) = -6√11 · √3/2 = -3√33