sentence1: How I find the sum of this series ? -LSB- math -RSB- \ displaystyle \ sum _ -LCB- k = 1 -RCB- ^ -LCB- \ infty -RCB- \ frac 1 k \ ln -LRB- \ frac 1 k + 1 -RRB- -LSB- / math -RSB-
sentence2: How do you find a sum of series -LSB- math -RSB- \ sum \ limits _ -LCB- k = 0 -RCB- ^ -LCB- \ infty -RCB- \ frac -LCB- -LRB- -1 -RRB- ^ n -RCB- -LCB- n ^ 23 ^ n -RCB- -LSB- / math -RSB- ?