Tính gtri biểu thức:P =\(\frac{5}{2.1}\)+\(\frac{4}{1.11}\)+\(\frac{3}{11.2}\)+\(\frac{1}{2.15}\)+\(\frac{13}{15.4}\)Q =\(\left(1-\frac{1}{2}\right)\).\(\left(1-\frac{1}{3}\right)\).\(\left(1-\frac{1}{4}\right)\).... \(\left(1-\frac{1}{20}\right)\)Giúp mị nha mina-san!...
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Tính gtri biểu thức:
P =\(\frac{5}{2.1}\)+\(\frac{4}{1.11}\)+\(\frac{3}{11.2}\)+\(\frac{1}{2.15}\)+\(\frac{13}{15.4}\)
Q =\(\left(1-\frac{1}{2}\right)\).\(\left(1-\frac{1}{3}\right)\).\(\left(1-\frac{1}{4}\right)\).... \(\left(1-\frac{1}{20}\right)\)
Giúp mị nha mina-san! :))
\(P=\frac{5}{2}+\frac{4}{11}+\frac{3}{22}+\frac{1}{30}+\frac{13}{60}=\left(\frac{4}{11}+\frac{3}{22}\right)+\left(\frac{5}{2}+\frac{1}{30}+\frac{13}{60}\right)=\frac{1}{2}+\frac{11}{4}=\frac{13}{4}\)
\(Q=\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)...\left(1-\frac{1}{20}\right)=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}...\frac{19}{20}=\frac{1.2.3....19}{2.3.4....20}=\frac{1}{20}\)
Cảm ơn mina-san nha! Mình đang tìm câu hỏi nào đáng tin cậy nhất rùi mới s