请问,1/(1*3)+1/(3*5)+1/(5*7)+……+1/(17*19)+1/(19*21)怎么计算?
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![请问,1/(1*3)+1/(3*5)+1/(5*7)+……+1/(17*19)+1/(19*21)怎么计算?](/uploads/image/z/33786-18-6.jpg?t=%E8%AF%B7%E9%97%AE%2C1%2F%EF%BC%881%2A3%EF%BC%89%2B1%2F%EF%BC%883%2A5%EF%BC%89%2B1%2F%EF%BC%885%2A7%EF%BC%89%2B%E2%80%A6%E2%80%A6%2B1%2F%2817%2A19%29%2B1%2F%2819%2A21%29%E6%80%8E%E4%B9%88%E8%AE%A1%E7%AE%97%3F)
请问,1/(1*3)+1/(3*5)+1/(5*7)+……+1/(17*19)+1/(19*21)怎么计算?
请问,1/(1*3)+1/(3*5)+1/(5*7)+……+1/(17*19)+1/(19*21)怎么计算?
请问,1/(1*3)+1/(3*5)+1/(5*7)+……+1/(17*19)+1/(19*21)怎么计算?
这个用的方法是裂项法,原式=1/2(1-1/3+1/3-1/5+1/5……-1/21)=1/2×(1-1/21)=10/21