Question

Tính tổng: 3+3/2+3/2^2+...+3/2^9

Answer 1

3+3/2+3/2²+...+3/2⁹

=3+3/2+3/4+...+3/512

=3(1+1/2+1/4+...+1/512)

=3(2-1+1-1/2+1/2-1/4+...+1/256-1/512)

=3(2-1/512)

=3.1/511/512=5/509/512