25. solve the equation n nC 2 = (n-1)(n+3/2) where n is a positive integer.
29. simplify ﹝(n-1)! (2n)!﹞/ 2(n!)(2n-2)!
更新1:
25. solve the equation n*nC2 = (n-1)(n+3/2) where n is a positive integer.
