0.2+0.4+0.6+0.8+0.10+0.12+0.14+…+0.98=
问题描述:
0.2+0.4+0.6+0.8+0.10+0.12+0.14+…+0.98=
答
0.2+0.4+0.6+0.8=2
下面考虑0.10+0.12+.+0.98
为a1=0.10,an=0.98的等差数列,n=45,则s45=45*a23=45*0.54=24.3
故总和为26.3