Question

Tính:
\(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right)...\left(1-\frac{1}{20}\right)\)

Answer 1

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

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

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

Answer 2

( 1 − 1/ 2 ) ( 1 − 1 /3 ) . . . ( 1 − 1/ 20 )
 = 1/ 2 . 2/ 3 . . . . 19/ 20
= 1/ 20