√n数列求和武忠祥

Question

如题所述

Answer 1

要求这n项和的话，只能求近似值
下面给一些参考公式，希望对你有所帮助
√1+√2+……+√n≈(3/2)*n^(3/2)+(1/2)*n^(1/2)
√1+√2+……+√n≈(3/2)*n^(3/2)+(1/2)*n^(1/2)-(1/6)
√1+√2+……+√n≈(3/2)*n^(3/2)+(1/2)*n^(1/2)+(1/24)*n^(-1/2)
√1+√2+……+√n≈(3/2)*n^(3/2)+(1/2)*n^(1/2)+(1/24)*n^(-1/2)-(5/24)
√1+√2+……+√n≈
(3/2)*n^(3/2)+(1/2)*n^(1/2)+(1/24)*n^(-1/2)-(1/1920)*n^(-5/2)-（399/1920）
√1+√2+……+√n≈
(3/2)*n^(3/2)+(1/2)*n^(1/2)+(1/24)*n^(-1/2)-(1/1920)*n^(-5/2)+(1/9216)*n^(-9/2)
-（9581/46080）