怎样计算下列各题~①1/2+1/4+1/6+1/31+1/62+1/124+1/248+1/496②1/42+5/42+11/42+13/42+17/42+19/42+23/42+25/42+29/42+31/42+37/42+41/42
问题描述:
怎样计算下列各题~
①1/2+1/4+1/6+1/31+1/62+1/124+1/248+1/496
②1/42+5/42+11/42+13/42+17/42+19/42+23/42+25/42+29/42+31/42+37/42+41/42
答
①1+1/2+1/4+1/8+1/16=2-1/16=31/161/2+1/4+1/6=11/121/31+1/62+1/124+1/248+1/496=1/31×(1+1/2+1/4+1/8+1/16)=1/31×31/16=1/16所以,1/2+1/4+1/6+1/31+1/62+1/124+1/248+1/496=31/16+1/16=2② 1 5 ...