求2+4+6+...+2n
16n^a+4n^3+6n^2+7^n=0,求n
求极限,根号(4n^2+n)
用夹逼定理求极限运用夹逼定理求下列序列的极限(6n^4+n-2)^(1/n)(lg3n)^(1/n)[2/(3n^2-n
求∑(2n)!/(n!)*4^n的敛散性.
求极限 lim(n->无穷)[(3n^2-2)/(3n^2+4)]^[n(n+1)]
求lim(n+1)(n+2)(n+3)/(n^4+n^2+1)
求[(1*2*4+2*4*8+…+n*2n*4n)/(1*3*9+2*6*18+...+n*3n*9n)]^2
跪求;(1*2*4+2*4*8+.n*2n*4n/1*3*9+2*6*18+.n*3n*9n)的平方.
1\n(n+3)+1\(n+3)(n+6)+1\(n+6)(n+9)=1\2 n+18 n为正整数,求n的值
若n为正整数,求1/n(n+1)+1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)+.+1/
若x^3n=2,试求x^6n+x^4n乘以x^5n的值
已知a^3n=5,b^2n=3 ,求a^6n b^4n