Question

Có ai đang buồn và lo lắng như này ko?

Help làm bài này: S = (1 + 2/3) . (1 + 2/5) . (1 + 2/7) ..... (1 + 2/89)

Thanks nhiều nha.

Answer 1

Tôi đây

Ko biết làm bt đó

# USAS - 12 # 

Answer 2

\(=\frac{5}{3}.\frac{7}{5}.\frac{9}{7}......\frac{91}{89}\)

\(=\frac{91}{3}\)

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Answer 3

\(S=\left(1+\frac{2}{3}\right).\left(1+\frac{2}{5}\right)....\left(1+\frac{2}{89}\right)\)

\(\Rightarrow S=\frac{5}{3}.\frac{7}{5}....\frac{91}{89}\)

\(\Rightarrow S=\frac{5.7.9.....89.91}{3.5.7.....87.89}\)

\(\Rightarrow S=\frac{91}{3}\)

Answer 4

S=(1+\(\frac{2}{3}\))x(1+\(\frac{2}{5}\))x.....x(1+\(\frac{2}{89}\))

S=\(\frac{5}{3}\)x\(\frac{7}{5}\)x.....x\(\frac{91}{89}\)

KHỬ LIÊN TIẾP THÌ ĐƯỢC

S=\(\frac{91}{3}\)

Answer 5

\(S=\left(1+\frac{2}{3}\right)\cdot\left(1+\frac{2}{5}\right)\cdot\left(1+\frac{2}{7}\right)\cdot\cdot\cdot\left(1+\frac{2}{89}\right)\)

\(S=\frac{5}{3}\cdot\frac{7}{5}\cdot\frac{9}{7}\cdot\cdot\cdot\frac{91}{89}\)

\(S=\frac{5\cdot7\cdot9\cdot\cdot\cdot91}{3\cdot5\cdot7\cdot\cdot\cdot89}\)

\(S=\frac{5\cdot7\cdot9\cdot\cdot\cdot89\cdot91}{3\cdot5\cdot7\cdot\cdot\cdot89}\)

\(S=\frac{91}{3}\)