$x^2+\sum_{k=1}^{\infty}\frac{1}{k^{s}}$

Question

test....

Answer 1

x²+∑1/kˢ where 1≤k<∞ and where s is undefined can have no general value because if s=0, the sum is infinite and the sum is infinite if s=1. For s<0, the sum is clearly infinite. So s>1. (Assume s is an integer?)  If y=x²+∑1/kˢ and s>1, x²+1<y<2.