计算,并从中在规律
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*(1+1/4)*(1-1/4)*(1+1/5)*(1-1/5)=( )
根据以上规律计算
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*……*(1+1/99)*(1-1/99)=
( )
为什么?
计算,并从中在规律
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*(1+1/4)*(1-1/4)*(1+1/5)*(1-1/5)=( )
根据以上规律计算
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*……*(1+1/99)*(1-1/99)=
( )
为什么?
因为(1+1/3)*(1-1/3)=(1)²-(1/3)²=(1/3)²(3²-1)
所以(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*(1+1/4)*(1-1/4)*(1+1/5)*(1-1/5)
=(1/2)²(2²-1)(1/3)²(3²-1)(1/4)²(4²-1)(1/5)²(5²-1)
=(1/2)²(1/3)²(1/4)²(1/5)²(2²-1)(3²-1)(4²-1)(5²-1)=0.6
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*……*(1+1/99)*(1-1/99)=
=(1/2)²(1/3)²(1/4)²(1/5)²*……*(1/99)² *(2²-1)(3²-1)(4²-1)(5²-1)*……*(99²-1)