计算：1-12+13-14+15-16+…[phone]+51+12+52+13+53+14+54+…+124+74+125+75．

Question

计算：(1-(1)/(2)+(1)/(3)-(1)/(4)+(1)/(5)-(1)/(6)+…+(1)/(49)-(1)/(50))/((1)/(1+51)+(1)/(2+52)+(1)/(3+53)+(1)/(4+54)+…+(1)/(24+74)+(1)/(25+75))．

Answer 1

根据分析的规律可得：
(1-(1)/(2)+(1)/(3)-(1)/(4)+(1)/(5)-(1)/(6)+…+(1)/(49)-(1)/(50))/((1)/(1+51)+(1)/(2+52)+(1)/(3+53)+(1)/(4+54)+…+(1)/(24+74)+(1)/(25+75))
=((1)/(26)+(1)/(27)+(1)/(28)+…+(1)/(50))/((1)/(2)((1)/(26)+(1)/(27)+(1)/(28)+…(1)/(50)))
=(1)/((1)/(2))
=2．