Question

Giúp mình với!

C= 3/1x2+3/2x3+3/4x5+....+3/2015x2016

Answer 1

sửa đề \(C=\frac{3}{1.2}+\frac{3}{2.3}+\frac{3}{3.4}+...+\frac{3}{2015.2016}\)

\(=3\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2015}-\frac{1}{2016}\right)\)

\(=3\left(1-\frac{1}{2016}\right)=3.\frac{2015}{2016}=\frac{2015}{672}\)