Добрый день! Пожалуйста, помогите решить примеры

Совсем просто1) u(n) = (n+1)!/(2n)u(1) = 2!/2 = 2/2 = 1u(2) = 3!/4 = 6/4 = 3/2u(3) = 4!/6 = 24/6 = 4u(4) = 5!/8 = 120/8 = 152) u(n) = (-1)^(n+1)*1/кор.куб.(n)u(1) = (-1)^2/1 = 1u(2) = (-1)^3/кор.куб.(2) = -1/кор.куб.(2)u(3) = (-1)^4/кор.куб.(3) = 1/кор.куб.(3)u(4) = (-1)^5/кор.куб.(4) = -1/кор.куб.(4)3) u(n) = 1/(3n-1)(2n+1)u(1) = 1/(3-1)(2+1) = 1/(2*3) = 1/6u(2) = 1/(6-1)(4+1) = 1/(5*5) = 1/25u(3) = 1/(9-1)(6+1) = 1/(8*7) = 1/56u(4) = 1/(12-1)(8+1) = 1/(11*9) = 1/99