Violympic toán 6
Các câu hỏi tương tự
Bài 1: Tính nhanh: \(\dfrac{4}{3.7}+\dfrac{4}{7.11}+\dfrac{4}{11.15}+\dfrac{4}{15.19}+\dfrac{4}{19.23}+\dfrac{4}{23.27}\)
Tính A , biết :
\(A=\dfrac{2}{11.15}+\dfrac{2}{15.19}+\dfrac{2}{19.23}+...+\dfrac{2}{51.55}\)
Cho \(A=\dfrac{1}{4}+\dfrac{1}{9}+\dfrac{1}{16}+...+\dfrac{1}{81}+\dfrac{1}{100}\)
Chứng tỏ \(A>\dfrac{65}{132}\)
Tính
A= \(\dfrac{2}{14.15}\)+\(\dfrac{2}{15.19}\)+\(\dfrac{2}{19.23}\)+\(\dfrac{2}{51.55}\)
Các bạn giúp với :Bài 1:a, CMR: A dfrac{3}{1^2.2^2}+dfrac{5}{2^2.3^2}+dfrac{7}{3^2.4^2}+...+dfrac{21}{10^2.11^2} 1b, Cho B dfrac{3}{4}+dfrac{8}{9}+dfrac{15}{16}+dfrac{24}{25}+...+dfrac{2499}{2500}. CMR: B không phải là số nguyên.c, So sánh: C dfrac{2}{2^1}+dfrac{3}{2^2}+dfrac{4}{2^3}+...+dfrac{2021}{2^{2020}} với 3.
Đọc tiếp
Các bạn giúp với :<
Bài 1:
a, CMR: A = \(\dfrac{3}{1^2.2^2}+\dfrac{5}{2^2.3^2}+\dfrac{7}{3^2.4^2}+...+\dfrac{21}{10^2.11^2}< 1\)
b, Cho B = \(\dfrac{3}{4}+\dfrac{8}{9}+\dfrac{15}{16}+\dfrac{24}{25}+...+\dfrac{2499}{2500}.\) CMR: B không phải là số nguyên.
c, So sánh: C = \(\dfrac{2}{2^1}+\dfrac{3}{2^2}+\dfrac{4}{2^3}+...+\dfrac{2021}{2^{2020}}\) với 3.
Cmr : \(\dfrac{1}{3}\) - \(\dfrac{2}{3^2}\) +\(\dfrac{3}{3^3}\) - \(\dfrac{4}{3^4}\) + ...+\(\dfrac{99}{3^{99}}\) - \(\dfrac{100}{3^{100}}\)< \(\dfrac{3}{16}\)
Tính tổng sau:
a) \(\dfrac{1}{9}+3,25+5\dfrac{3}{16}+4\dfrac{1}{3}+2,8+0,5\)
b) \(2\dfrac{1}{3}+0,45+4,25+\dfrac{1}{81}+6\dfrac{8}{27}\)
c) \(1,25+2\dfrac{1}{4}+4\dfrac{2}{5}+0,3+2,14+4\dfrac{1}{8}\)
CMR \(\dfrac{1}{3}-\dfrac{2}{3^2}+\dfrac{3}{3^3}-\dfrac{4}{3^4}+...+\dfrac{99}{3^{99}}-\dfrac{100}{3^{100}}< \dfrac{3}{16}\)
CMR \(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{8}-\dfrac{1}{16}+\dfrac{1}{32}-\dfrac{1}{64}< \dfrac{1}{3}\)