(1-1/2²)(1-1/3²)(1-1/4²)…(1-1/100²)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)...........(1-1/100)(1+1/100)
=1/2*3/2*2/3*4/3..........99/100*101/100
=1/2*101/100
=101/200
解:
原式=(1-1/2)(1+1/2)(1-1/3)(1+1/3)(1-1/4)(1+1/4)×… ×(1-1/100)(1+1/100)
= 1/2× 3/2 × 2 /3×4/3×3/4×5/4×… ×99/100×101/100
=1/2×101/100
=101/200
101/200