Question

[trần khánh thy]

A=\(\frac{1}{2}\)+\(\frac{1}{2^2}\)+\(\frac{1}{2^3}\)+....+\(\frac{1}{2^9}\)

B=\(\frac{1}{4}\)+\(\frac{1}{12}\)+\(\frac{1}{30}\)+....+\(\frac{1}{972}\)

C= 1+\(\frac{1}{2}\)(1+2)+\(\frac{1}{3}\)(1+2+3)+....+\(\frac{1}{20}\)(1+2+3+....+20)

 LÀM ƠN GIÚP MÌNH NHA ;^;

Answer 1

[boy trung học]

chỉ cần ns 1 từ dễ