原式=1/2(1-1/3+1/3-1/5+...+/2011-1/2013)+1/2(1/2-1/4+1/4-1/6+...+1/2012-1/2014)=1/2(1-1/2013)+1/2(1/2-1/2014)=1/2×2012/2013+1/2×1006/2014=1006/2013+503/2014=3038623/4054182