1/1×3+1/3×5+1/5×7+……+1/47×49

问题描述:

1/1×3+1/3×5+1/5×7+……+1/47×49
简便计算

1/1*3+1/3*5+1/5*7+.+1/47*49
=1/2*(1-1/3+1/3-1/5+1/5-1/7+...+1/47-1/49)
=1/2(1-1/49)
=1/2*48/49
=24/49