灬Hero丶镖灬:
原式=(1-1/2)(1+1/2)(1-1/3)(1+1/3)×……×(1-1/12)(1+1/12)
=(1/2)×(3/2)×(2/3)×(4/3)×……×(11/12)×(13/12)
=(1/2)×[(3/2)×(2/3)×(4/3)×(3/4)×……×(12/11)×(11/12)]×(13/12)
=(1/2)×(13/12)
=13/24
灬Hero丶镖灬:
原式=(1-1/2)(1+1/2)(1-1/3)(1+1/3)×……×(1-1/12)(1+1/12)
=(1/2)×(3/2)×(2/3)×(4/3)×……×(11/12)×(13/12)
=(1/2)×[(3/2)×(2/3)×(4/3)×(3/4)×……×(12/11)×(11/12)]×(13/12)
=(1/2)×(13/12)
=13/24