## Calculus (3rd Edition)

It is impossible to find $N$ such that the partial sum $S_N\gt 25$.
The series $$\Sigma_{n=1}^\infty \frac{1}{n^n}$$ is a geometric series with the sum $$\frac{1/2}{1-1/2}=1$$ So it is impossible to find $N$ such that the partial sum $S_N\gt 25$.