对于任意的正整数n,有1/1*2*3 + 1/2*3*4 +...1/n(n+1)(n+2)
来源:学生作业帮 编辑:大师作文网作业帮 分类:数学作业 时间:2024/11/11 06:59:48
对于任意的正整数n,有1/1*2*3 + 1/2*3*4 +...1/n(n+1)(n+2)
解 1/n(n+1)(n+2)
=[1/n-1/n+1](1/n+1)
=1/n(n+1)-1/(n+1)(n+2)
=1/2(1/n-1/n+2)-1/n+1+1/n+2
=1/2[1/n+1/n+2-2/n+1]
=1/2[1/n-1/n+1+1/n+2-1/n+1]
所以 1/1*2*3 +1/2*3*4+...+1/n(n+1)(n+2)
=1/2(1-1/2+1/3-1/2+1/2-1/3+1/4-1/3+1/3-1/4+1/5-1/4+...+1/n-1/n+1+1/n+2-1/n+1)
=1/2[1-1/2+1/(n+1)(n+2)]
=1/4-1/2(n+1)(n+2)
因为1/2(n+1)(n+2)>0 所以-1/2(n+1)(n+2)
=[1/n-1/n+1](1/n+1)
=1/n(n+1)-1/(n+1)(n+2)
=1/2(1/n-1/n+2)-1/n+1+1/n+2
=1/2[1/n+1/n+2-2/n+1]
=1/2[1/n-1/n+1+1/n+2-1/n+1]
所以 1/1*2*3 +1/2*3*4+...+1/n(n+1)(n+2)
=1/2(1-1/2+1/3-1/2+1/2-1/3+1/4-1/3+1/3-1/4+1/5-1/4+...+1/n-1/n+1+1/n+2-1/n+1)
=1/2[1-1/2+1/(n+1)(n+2)]
=1/4-1/2(n+1)(n+2)
因为1/2(n+1)(n+2)>0 所以-1/2(n+1)(n+2)
证明对于大于1的任意正整数n都有 In n>1/2+1/3+1/4+...1/n
对于任意正整数n,求证:ln(1/2+1/n)>1/n^2-2/n-1
证明对任意正整数n,不等式ln(1/n+1)>1/n^2-1/n^3
证明:对任意的正整数n,有1/1×3+1/2×4+1/3×5+.+1/n(n+2)
1/n+1+1/n+2+1/n+3+...+1/2n>m/24n对于一切n∈n都成立,则正整数m的最大值为
用数学归纳法证明对于任意大于1的正整数n,不等式1/(2^2)+1/(3^2)+…+1/(n^2) 小于(n-1)/n
不等式数学证明题证明:对于任意的正整数n,不等式ln(1/n+1)>1/n^2-1/n^3都成立
对于任意大于1的整数n,大于n!+n而小于n!+n的质数的个数有多少个?(其中n!=n*(n-1)*(n-2)*.*3*
证明对任意的正整数n,不等式ln(1/n+1)>1/n^2-1/n^3都成立
对于任意正整数n,猜想2n-1与(n+1)2的大小关系,并给出证明.
对大于1的任意正整数n,都有1+1/2+1/3+1/4+...+1/n>ln(e^n/n!)
证明:对任意的正整数n,不等式2+3/4+4/9+…+(n+1)/n^2>In(n+1)都成立!若bn=(n-2)*(1