(1-1/2²)(1-1/3²)(1-1/4²)…(1-1/2012²)(1-2013²)（1-1/2014²）
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)(1-1/4)(1+1/4)×.×(1-1/2013)(1+1/2013)(1-1/2014)(1+1/2014)
=1/2×3/2×2/3×4/3×3/4×5/4×.×2011/2012×2013/2012×2012/2013×2014/2013×2013/2014×2015/2014
=1/2×2015/2014
=2015/4028