求证 1^3+2^3+3^3+...+n^3=(1+2+3+
求证:3/2-1/n+1
求证c(n,1)+2c(n,2)+3c(n,3)+...+nc(n,n)=n2^(n-1)
数学定理证明求证2^n-1=2^n-1+2^n-2+2^n-3+.+2^n-n
求证1/(n+1)+1/(n+2)+.+1/(3n+1)>1 [n属于N*]
当n为正偶数,求证n/(n-1)+n(n-2)/(n-1)(n-3)+...+n(n-2).2/(n-1)(n-3)..
求证1!+2*2!+3*3!+…+n*n!=(n+1)!-1
求证1+1/2+1/3+...+1/n>In(n+1) (n属于N+)
求证:1+1/2+1/3+...+1/n>In(n+1)+n/2(n+1) (n属于N+)
已知Sn=1+1/2+1/3+.+1/n(n>1,n为整数),求证S(2^n)>1+n/2(n>=2,n为整数)
求证:1*2+2*5+3*8+…+n(3n-1)=n^2(n+1)
f(n)=1+(1/2)+(1/3)+.(1/n) 求证:f(2的n次方)>(n+2)/2
求证:1²+2²+3²+……+n²=[n(n+1)(n+2)]/6