1/1*3+1/3*5+1/5*7+.+1/99*101

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1/1*3+1/3*5+1/5*7+.+1/99*101
1/1*3+1/3*5+1/5*7+.+1/99*101

1/1*3+1/3*5+1/5*7+.+1/99*101
1/1*3+1/3*5+1/5*7+...+1/99*101
=(1-1/3)÷2+(1/3-1/5)÷2+(1/5-1/7)÷2+……+(1/99-1/101)÷2
=[(1-1/3)+(1/3-1/5)+(1/5-1/7)+……+(1/99-1/101)]÷2
=(1-1/3+1/3-1/5+1/5-1/7+……+1/99-1/101)÷2
中间互相抵消
=(1-1/101)÷2
=100/101÷2
=50/101
参考资料:仅供参考,

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1/n*(n+2)=1/2*{1/n-1/(n+2)}

(1-1/3)/2+(1/3-1/5)/2+...+(1/99-1/101)/2
=(1-1/3+1/3-1/5+1/5-1/7+...+1/99-1/101)/2
=(1-1/101)/2
=(100/101)/2
=50/101