Question

Tính \(B=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)...\left(1-\frac{1}{20}\right)\)

Answer 1

\(B=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).....\left(1-\frac{1}{20}\right)\)

\(B=\frac{1}{2}.\frac{2}{3}.....\frac{19}{20}\)

\(B=\frac{1}{20}\)

Answer 2

B = \(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)...\left(1-\frac{1}{20}\right)\)

B = \(\frac{1}{2}.\frac{2}{3}.\frac{3}{4}...\frac{19}{20}\)'

B = \(\frac{1}{20}\)

Vậy B = \(\frac{1}{20}\)

Answer 3

\(B=\frac{1}{2}.\frac{2}{3}.....\frac{19}{20}\)

\(B=\frac{1.2.3...19}{2.3.4...20}=\frac{1}{20}\)

Hok tốt

Answer 4

\(B=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{20}\right)\)

\(B=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}....\frac{19}{20}\)

\(B=\frac{1}{20}\)

Vậy \(B=\frac{1}{20}\)

Answer 5

B  = (1 - 1/2)(1 - 1/3)(1 - 1/4)...(1 - 1/20)

B = 1/2.2/3.3/4.....19/20

B = 1/20