(2n+1)²- (2n-1)²=8n 化简
根号【(2n+1)/(n²+n)】平方-4/(n平方+n )化简
若n²+3n=1,求n(n+1)(n+2)+1的值.
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
2^n/n*(n+1)
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
化简(n+1)(n+2)(n+3)
比较2n-1和n²*n-3n²-2n+6
化简[n^2+(n+1)^2]/n(n+1) 化简额
阶乘(2n-1)!=(2n)!/(2^n*n!
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?
1 + (n + 1) + n*(n + 1) + n*n + (n + 1) + 1 = 2n^2 + 3n + 3
先化简再求值[(m+n)(m-n)-(m-n)²]÷(2n),其中m=-2,n=-1/2