丨5n/n+1 - 5丨

丨5n/n+1 - 5丨 2^n*3^n*5^(n+1)/30^n 3(n-1)(n+3)-2(n-5)(n-2) Sn=n(n+2)(n+4)的分项等于1/6[n(n+2)(n+4)(n+5)-(n-1)n(n+2)(n+4)]吗? n+(n+1)+(n+2)+(n+3)+(n+4)=5n+10这道题怎么解 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, 1+(n+2)+(2n+3)+(3n+4)+(4n+5)+……((n-1)n+n)的答案 4^n+4^(n-1)C1/n+4^(n-2)C2/n+...+Cn/n=答案是5^n. 解方程(2n+1)(n+1)n-(2n-21)(n-10)(n-11)=2(2n-9)(n-4)(n-5) lim {（-4）^n+5^n}/{4^(n+1) + 5^(n+1)} n→无限 (5^n+(-2)^n)/(5^(n+1)+(-2)^(n+1))当n趋近无穷,求极限. lim(3^2n+5^n)/(1+9^n)3^2n or 5^n 解方程 n（n+1）=n2+5n+6-n（n+1）解； 求limn→无穷(1+2^n+3^n+4^n+5^n)^1/n 求证：N=(5^2)*(3^2n+1)*(2^n)-(3^n)*(6^n+2) 3n²-n=1 求6n³+7n²-5n+2014 已知n平方-n-1=0,则n三方-n平方-n+5=? 已知n＾2-n -1=0,则n^3-n^2-n +5=