The series {(x/5) n/n}, n from 1 to oo} is conditionally convergent at x = -5, but the convergence radius of this series is 5.

Because the power series converges to x= 1, then according to Abel's theorem, it is concluded that x= 1 is one of its endpoints, that is, when | x | exists; 0, for any x 1, x2 satisfies 0.

The definition of convergence well embodies the spiritual essence of mathematical analysis.

Given a function sequence defined on the interval I, u 1(x), u2(x), u3(x) ... to the United Nations (x) ... and then the expression U 1 (x)+U2 (x)+U3 (x)+

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