Các câu hỏi tương tự
\(A=\frac{1}{72}+\frac{1}{90}+........+\frac{1}{9702}+\frac{1}{9900}\)
\(B=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)
giải nhanh giùm mk nha (nhớ là có lời giải đấy)
Tính nhanh
\(\frac{1}{15}+\frac{4}{30}+\frac{9}{45}+\frac{16}{60}+\frac{25}{75}+\frac{36}{90}+\frac{49}{105}+\frac{64}{120}+\frac{81}{135}\)
1/TINH
\(\frac{3}{2}-\frac{5}{6}+\frac{7}{12}-\frac{9}{20}+\frac{11}{30}-\frac{13}{42}+\frac{15}{56}-\frac{17}{72}+\frac{19}{90}\)
\(\frac{2^3}{1.3}.\frac{3^2}{2.4}.\frac{4^2^{^{^{ }}}}{3.5}......\frac{99^2}{98.100}\)
2/CMR
\(\frac{1}{4}+\frac{1}{16}+\frac{1}{36}+\frac{1}{64}+\frac{1}{100}+\frac{1}{144}+\frac{1}{196}+...+\frac{1}{10000}< \frac{1}{2}\)
cho:
a) A= 2+\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{62}+\frac{1}{63}+\frac{1}{64}+\frac{1}{65}+\frac{1}{66}+\frac{1}{67}\)
chứng minh rằng A>5
b) B= \(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{89^2}+\frac{1}{90^2}\)
chứng minh rằng \(\frac{40}{91}\)<B<1
Bài 1 : tính giá trị biểu thức :
a) \(\left(\frac{215}{2010}-\frac{120}{2011}\right)\)x \(\left(\frac{1}{3}-\frac{1}{4}-\frac{1}{12}\right)\)
b) ( 45 x 46 +47 x 48 ) ( 45 x 128 - 90 x 64 ) ( 2009 x 2010 + 2011 x 2012 )
\(B=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}=?\)
HB
17 tháng 3 2016 lúc 19:47
Cho A=\(\frac{\frac{1}{5}+\frac{1}{7}-\frac{1}{13}}{\frac{3}{5}+\frac{3}{7}-\frac{3}{13}}.\frac{\frac{3}{4}-\frac{3}{16}+\frac{1}{64}-\frac{3}{256}}{1-\frac{1}{4}+\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
a) Rút gọn A
b) tính 75% của A
Tinh
D= \(\frac{\frac{1}{3}+\frac{1}{17}-\frac{1}{13}}{\frac{2}{3}+\frac{2}{17}-\frac{2}{13}}.\frac{\frac{3}{4}-\frac{3}{16}+\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}+\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
Trinh bay cach lam nhe
Ko hieu vao DOC THEM
Tính
a) \(\frac{1}{5}+\frac{-1}{6}+\frac{1}{7}+\frac{1}{-8}+\frac{1}{9}+\frac{1}{8}+\frac{1}{-7}+\frac{-1}{6}+\frac{-1}{5}\)
b) (-11).36-64.11
c) \(\frac{\frac{1}{3}+\frac{1}{7}+\frac{1}{13}}{\frac{2}{3}+\frac{2}{7}+\frac{2}{13}}.\frac{\frac{3}{4}+\frac{3}{16}+\frac{3}{64}+\frac{3}{256}}{1+\frac{1}{4}+\frac{1}{16}+\frac{1}{64}}+\frac{3}{8}\)