求(1-1/2^2)*(1-1/3^)*(1-1/4^)*……*(1-1/99^2)*(1-1/100^2)的值
问题描述:
求(1-1/2^2)*(1-1/3^)*(1-1/4^)*……*(1-1/99^2)*(1-1/100^2)的值
答
(1-1/2^2)*(1-1/3^)*(1-1/4^)*……*(1-1/99^2)*(1-1/100^2)=1/2*3/2*2/3.......99/100*101/100=101/200
答
(1-1/2^2)*(1-1/3^)*(1-1/4^)*……*(1-1/99^2)*(1-1/100^2)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)*.(1-1/99)(1+1/99)(1-1/100)(1+1/100)
=(1/2)*(3/2)(2/3)*(4/3)*.(98/99)*(100/99)(99/100)(101/100)
=(1/2)*(101/100)
=101/200
提示:运用平方差公式