Question

Cho biểu thức A = 1/1*2*3+1/2*3*4+1/3*4*5+...+1/2015*2016*2017

Answer 1

Mk ko bt t mình nhé mk mới giam gia thôi

Answer 2

\(A=\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{2015.2016.2017}\)

\(A=\frac{3-1}{1.2.3}+\frac{4-2}{2.3.4}+\frac{5-3}{3.4.5}+...+\frac{2017-2015}{2015.2016.2017}\)

\(2A=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{2015.2016}-\frac{1}{2016.2017}\)

\(2A=\frac{1}{1.2}-\frac{1}{2016.2017}\)

\(A=\left(\frac{1}{1.2}-\frac{1}{2016.2017}\right)\div2\)