2^n-2^(n+1)怎么化简

(n+1)+n+(n-1)+(n-2)…+3+2+1怎么化简 2^n-2^(n+1)怎么化简 (3n+1)/(2n+1)怎么化简! n+(n+1)+(n+2)+(n+3)+(n+4)=5n+10这道题怎么解 lim[n/(n*n+1*1)+n/(n*n+2*2)+...+n/(n*n+n*n)],当x趋向无穷大时,怎么求极限, (m n)!/(m n-2)!-n!/(n-2)!=62怎么化简 (m+n)!/(m+n-2)!-n!/(n-2)!=62怎么化简 lim(n→+∞)([C,2,n]+2[C,n-2,n])/(n+1)^2 C代表排列组合2是上标n是下标 求极限,化简得lim(n→+∞){3/2*[P,2,n]}/（n+1)^2=lim(n→+∞){3/2*n(n-1)}/(n+1)^2求接下来怎么化 （n+1)-根号(n+1)^2+1/n-根号n^2+1=n+根号n^2+1/(n+1)+根号(n+1)^2+1 前一步到后一步是怎么化简的? 1＋2C(n,1)＋4C(n,2)＋……＋(2^n－1)C(n,n－1)＋(2^n)C(n,n)怎么化简, (n-1)^2怎么化简 1/[n(n+1)]+1/[(n+1)(n+2)]+1/[(n+2)(n+3)]+1/[(n+3)(n+4)]+[(n+4)(n+5)}怎么算谢谢了, 2^n/n*(n+1) 根号下n(n+1)(n+2)(n+3)+1 的化简怎样化简 根号下n(n+1)(n+2)(n+3)+1 证明不等式：(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n n-2+n-1+n+n+1+n+2怎么算 1/n(n+1)(n+2)求和怎么做 怎么化简(2n²+2n)²=?