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
答
1/1×3+1/3×5+1/5×7······﹢1/47×49
=1/2×(1-1/3)+1/2×(1/3-1/5)+...+1/2×(1/47-1/49)
=1/2×(1-1/3+1/3-1/5+1/5-1/7+...+1/47-1/49)
=1/2×(1-1/49)
=24/49