A= 101 100 99 ... 2 1− + − + − +101 100 99 98 ... 2 1HD

101.51 5151

TS + 2

( 101 100 ) ( 99 98 ) ... ( 3 2 ) 1 1 1 ... 1 51

A TS

MS = − + − + + − + = + + + = . Khi đó: 51.101

51 101

= MS = =

+ + +