1/2(1+1/2)(1+1/4)(1+1/16)
=(1-1/2)(1+1/2)(1+1/4)(1+1/16)
=(1-1/4)(1+1/4)(1+1/16)
=(1-1/16)(1+1/16)
=1-1/256
=255/256
(1-1/2)(1+1/2)(1+1/4)(1+1/16)=(1-1/4)(1+1/4)(1+1/16)=(1-1/16)(1+1/16)=1-1/256=255/256
(1-1/2)(1+1/2)(1+1/4)(1+1/16)
=【1-(1/2)²】(1+1/4)(1+1/16)
=(1-1/16)(1+1/16)
=1-1/256=255/256