1/2+1/6+1/18+1/54+1/162+1/486
Những câu hỏi liên quan
1/2 + 1/6 + 1/18 + 1/54 + 1/162 + 1/486 + 1/1458
1/2+1/6+1/18+1/54+1/162+1/486
Tính nhanh
Tính bằng cách thuận tiện nhất
1/2 + 1/6 + 1/18 + 1/54 + 1/162 + 1/486
\(A=\frac{1}{2}+\frac{1}{6}+\frac{1}{18}+\frac{1}{54}+\frac{1}{162}+\frac{1}{486}\)
\(3\times A=\frac{3}{2}+\frac{1}{2}+\frac{1}{6}+\frac{1}{18}+\frac{1}{54}+\frac{1}{162}\)
\(3\times A-A=\left(\frac{3}{2}+\frac{1}{2}+\frac{1}{6}+\frac{1}{18}+\frac{1}{54}+\frac{1}{162}\right)-\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{18}+\frac{1}{54}+\frac{1}{162}+\frac{1}{486}\right)\)
\(2\times A=\frac{3}{2}-\frac{1}{486}\)
\(A=\frac{182}{243}\)
bài 6 : NÂNG CAO LỚP 5 TÍNH NHANH
a= 1/2=1/6+1/18+1/54+1/162+1/486
1/2 + 1/6 + 1/18 + 1/54 + 1/162 + 1/486 + 1/1458
Giá trị của biểu thứ trên là một phân số tối giản
1.b=5/2+5/6+5/18+5/54+5/162+5/486
2.c=3/2+3/8+3/32+3/128+3/512
A= 1/2+1/6+1/18+1/54+1/162
\(A=\frac{1}{2}+\frac{1}{6}+\frac{1}{18}+\frac{1}{54}+\frac{1}{162}\)
\(A=\frac{81}{162}+\frac{27}{162}+\frac{9}{162}+\frac{3}{162}+\frac{1}{162}\)
\(A=\frac{\left(81+9\right)+\left(27+3\right)+1}{162}\)
\(A=\frac{90+30+1}{162}\)
\(A=\frac{121}{162}\)
Xem thêm câu trả lời
Tính nhanh: 1/2+1/6+1/18+1/54+1/162
1/
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{18}+\frac{1}{54}+...+\frac{1}{486}\)
