1/50-1/50.49-1/49.48-...-1/2.1
giúp mình với please=)
Rút gọn \(A=\dfrac{1}{100}-\dfrac{1}{100.99}-\dfrac{1}{99.98}-\dfrac{1}{98.97}-...-\dfrac{1}{3.2}-\dfrac{1}{2.1}\)
Tính: \(B=\dfrac{-1}{99}+\dfrac{1}{99.98}-\dfrac{1}{98.97}-...-\dfrac{1}{2.1}\)
Giải chi tiết dùm mình nhe. Thanks
Tính tỉ số a và b biết:
\(A\)=92-\(\dfrac{1}{9}\)-\(\dfrac{2}{10}\)-\(\dfrac{3}{11}\)-...-\(\dfrac{92}{100}\);
\(B\)=\(\dfrac{1}{45}\)+\(\dfrac{1}{50}\)+\(\dfrac{1}{55}\)+...+\(\dfrac{1}{500}\)
Giúp mình nha cảm ơn bạn nhiều lắm!
A= \(\dfrac{1}{50}-\dfrac{1}{6}-\dfrac{1}{12}-\dfrac{1}{20}-\dfrac{1}{30}-\dfrac{1}{42}\)
A=\(\left[\dfrac{1\dfrac{11}{31}.4\dfrac{3}{7}-\left(15-6\dfrac{1}{3}.\dfrac{2}{19}\right)}{4\dfrac{5}{6}+\dfrac{1}{6}\left(12-5\dfrac{1}{3}\right)}.\left(-1\dfrac{14}{93}\right)\right].\dfrac{31}{50}\)
Chứng minh rằng:
\(\dfrac{1}{1.2}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+...+\dfrac{1}{49.50}=\dfrac{1}{26}+\dfrac{1}{27}+...+\dfrac{1}{50}\)
Tính
a) \(\dfrac{13}{50}.\left(-15.5\right):\dfrac{13}{50}.84\dfrac{1}{2}\)
b) \(\dfrac{\left(-0,7\right)^2.\left(-5\right)^3}{\left(-2\dfrac{1}{3}\right)^3.\left(1\dfrac{1}{2}\right)^4.\left(-1\right)^5}\)
Chứng minh rằng: \(\dfrac{1}{1\cdot2}+\dfrac{1}{3\cdot4}+\dfrac{1}{5\cdot6}+...+\dfrac{1}{49\cdot50}=\dfrac{1}{26}+\dfrac{1}{27}+\dfrac{1}{28}+...+\dfrac{1}{50}\)
help mik với
tính \(B=\dfrac{1}{3}+\dfrac{1}{3^2}-\dfrac{1}{3^3}+...+\dfrac{1}{3^{50}}-\dfrac{1}{3^{51}}\)