This Calculus Question is Difficult #maths

So the part where I describe the Stolz-Cesaro Lemma is slightly inaccurate. I was using a specific case of the Stolz-Cesaro Lemma. Check out the full lemma here: https://en.wikipedia.org/wiki/Stolz%E2%80%93Ces%C3%A0ro_theorem The video applies the Stolz-Cesaro Lemma, but the general statement only requires that the sequence {b_n} is monotone and diverges to either +∞ or -∞. Technically, {a_n} doesn't have to converge or diverge, so perhaps part of the proof was redundant (the part where I used the p-series test). Like I said earlier, the proof uses a specific case where the SC Lemma applies.