\(A=\frac{88}{25}-2\left(\frac{9}{20}-\frac{11}{30}+\frac{13}{42}-.....-\frac{199}{9900}\right)\)
\(A=\frac{88}{25}-2\left(\frac{4+5}{4.5}-\frac{5+6}{5.6}+....-\frac{99+100}{99.100}\right)\)
\(A=\frac{88}{25}-2\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{5}-\frac{1}{6}+\frac{1}{6}+....-\frac{1}{99}-\frac{1}{100}\right)\)
\(A=\frac{88}{25}-2\left(\frac{1}{4}-\frac{1}{100}\right)=\frac{88}{25}-\frac{1}{2}+\frac{1}{50}=\frac{176-25+1}{50}=\frac{152}{50}=\frac{76}{25}\)
Tính tổng:
\(S=\frac{38}{25}+\frac{9}{10}-\frac{11}{15}+\frac{13}{21}-\frac{15}{28}+\frac{17}{36}-...+\frac{197}{4851}-\frac{199}{4950}\)
Tính tổng :
\(A=\frac{38}{25}+\frac{9}{10}-\frac{11}{15}+\frac{13}{21}-\frac{15}{28}+\frac{17}{36}-...+\frac{197}{4851}-\frac{199}{4950}\)
Tính tổng : \(S=\frac{38}{25}+\frac{9}{10}-\frac{11}{15}+\frac{13}{21}-\frac{15}{28}+\frac{17}{36}-...+\frac{197}{4851}-\frac{199}{4950}\)
Tính : \(Q=\frac{85}{25}+\frac{9}{10}-\frac{11}{5}+\frac{13}{21}-\frac{15}{28}+\frac{17}{36}-...+\frac{197}{4851}-\frac{199}{4950}\)
BÀI THI HỌC SINH GIỎI
Cho \(Q=\frac{13}{25}+\frac{9}{10}-\frac{11}{25}+\frac{13}{21}-\frac{15}{28}+\frac{17}{36}-...+\frac{197}{4851}-\frac{199}{4950}\). CMR : \(Q>\frac{9}{10}\)
Câu này t nhìn quen quen nhưng ko bt lm...
Tim x \(\in\) Z biet :\(2.\left(x-2\right)^2=\frac{38}{25}+\frac{9}{10}-\frac{11}{15}+\frac{13}{21}-\frac{15}{28}+\frac{17}{36}-...+\frac{197}{4851}-\frac{199}{4950}\)
Tính tổng: A =\(\frac{38}{25}\)+ \(\frac{9}{10}\)- \(\frac{11}{15}\)+ \(\frac{13}{21}\) - \(\frac{15}{28}\) + \(\frac{17}{36}\)- ..... + \(\frac{197}{4851}\)- \(\frac{199}{4950}\)
Cho A = 13/25 + 9/10 - 11/15 + 13/21 - 15/28 + 17/36 - ... + 197/4851 - 199/4950 chứng minh rằng A > 9/10
Cho
\(A=\frac{3^3}{1}-\frac{5^3}{3}+\frac{7^3}{6}-\frac{9^3}{10}+\frac{11^3}{15}-\frac{13^3}{21}+\frac{15^3}{28}-\frac{17^3}{36}+...+\frac{199^3}{4950}\)
So sánh A với 814.
Mọi người giúp em câu này với ạ! Em cảm ơn!
