1又2/3+2又2/15+3又2/35+.+11又2/483+12又2/575

1又2/3+2又2/15+3又2/35+.+11又2/483+12又2/575
1又2/3+2又2/15+3又2/35+.+11又2/483+12又2/575

1又2/3+2又2/15+3又2/35+.+11又2/483+12又2/575
原式=1+2+3+...+11+12+2/3+2/15+2/35+...+2/483+2/575
=(1+12)*12/2+2*(1/3+1/15+1/35+...+1/483+1/575)
=78+2*[1/(1*3)+1/(3*5)+1/(5*7)+...1/(21*23)+1/(23*25)]
=78+2*1/2*(1/1-1/3+1/3-1/5+1/5-1/7+...+1/21-1/23+1/23-1/25)
=78+(1-1/25)
=78+24/25
=78又24/25