1×3分之2002+3×5分之2002+5×7分之2002+7×9分之2002+9×11分之2002
=2002/(1*3)+2002/(5*7)+2002/(7*9)+2002/(9*11)
=2002*[1/2(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11)
=1001(1-1/11)
=1001*10/11
=910
1×3分之2002+3×5分之2002+5×7分之2002+7×9分之2002+9×11分之2002
=2002/(1*3)+2002/(5*7)+2002/(7*9)+2002/(9*11)
=2002*[1/2(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11)
=1001(1-1/11)
=1001*10/11
=910