Đáp án:
`C = 11/20`
Giải thích các bước giải:
`c, C = ( 1 - 1/2^2 ) . ( 1 - 1/3^2 ) . ( 1 - 1/4^2 ) ........... ( 1 - 1/10^2 )`
`C = ( 1 - 1/4 ) . ( 1 - 1/9 ) . ( 1 - 1/16 ) .......... ( 1 - 1/100 )`
`C = 3/4 . 8/9 . 15/16 .......... 99/100`
`C = 3/4 . 2.4/3.3 . 3.5/4.4............. 9.11/10.10`
`C = 3/4 . (2.3.............9)/(3.4.............10) . ( 4.5............11 )/( 3.4.............10 )`
`C = 3/4 . 2/10 . 11/3`
`C = 3/20 . 11/3`
`C = 11/20`
