Question and Answers Forum

All Questions      Topic List

Algebra Questions

Previous in All Question      Next in All Question      

Previous in Algebra      Next in Algebra      

Question Number 165532 by mathlove last updated on 03/Feb/22

Answered by amin96 last updated on 03/Feb/22

$$\mathbf{S}=\underset{\mathbf{n}=2}{\sum ^{\mathrm{\infty }}}\frac{1}{{\mathbf{n}}^2-1}=\underset{\mathbf{n}=2}{\sum ^{\mathrm{\infty }}}\frac{1}{(\mathbf{n}-1)(\mathbf{n}+1)}=$$$$=\frac{1}{2}\underset{\mathbf{n}=2}{\sum ^{\mathrm{\infty }}}\frac{1}{\mathbf{n}-1}-\frac{1}{2}\underset{\mathbf{n}=2}{\sum ^{\mathrm{\infty }}}\frac{1}{\mathbf{n}+1}=$$$$=\frac{1}{2}(1+\frac{1}{2}+\frac{1}{3}+\dots -(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\dots ))=$$$$=\frac{1}{2}(1+\frac{1}{2})=\frac{3}{4}$$

Terms of Service

Privacy Policy

Contact: info@tinkutara.com