解:(1-1/4)(1-1/9)...(1-1/99^2)=50/99
过程见附图。
1-1/n^2=(n-1)(n+1)/n²
原式=(1/2) *(3/2) * (2/3) *(4/3) * (3/4)*(5/4) *.......*98/99 * 100/99
=(1/2) * (100/99)
=50/99
原式=(1-(1/2)^2)(1-(1/3)^2)...(1-(1/99)^2)
=(1+1/2)(1-/2)(1+1/3)(1-1/3)...(1+1/99)(1-1/99)
=1/2*3/2*2*/3*4/3*3/4*5/4...97/98*99/98*98/99*100/99
=1/2*100/99
=50/99