From a purely practical point of view: how you answer an older question might be different than how you answer a new question.
Is frowned upon to do so?
There's nothing frowned upon. The only answers people frown upon here are when people post complete solutions to homework problems where there is no apparent effort in the question to solve the problem.
For your example, the person asking the question last visited the site in March 2016 (almost 3 years ago). Meaning when you answer their question, most likely they won't see your answer. Therefore you probably want to write your answer with the community in mind rather than the person asking the question. This stuff you put into your answer:
Have you considered the following?
Let me know if you need more details.
It's strange because there's a good possibility the person asking the question is never going to see your answer.
I suggest the following practical advice:
If the person who asked the question is still active on this site (which you can see from their user profile) then you can treat the old question the same as any other question.
- Although if it looked like a homework problem when it was posted, it's probably not the questioner's homework anymore.
If the person who asked the question hasn't been seen in months or years then generally your answers should be useful to the community and the person who originally asked the question is all but irrelevant.
- If an answer seems like it would only be useful to the person who asked the problem, then your time is better spent on other questions.
- If you're giving hints rather than a complete solution, then tailor your hints to the problem rather than the work shown in the question (because if it's tailored to the work shown then it's tailored to the questioner).
- Possibly this involves repeating some of the work shown in the question as part of the solution sketch.
- If I lean a certain amount towards giving hints rather than complete solutions to new questions, I might lean a little more towards complete solutions for older problems. For new questions, if your hint or lack of details confuses a large number of people, then you will get a follow-up comment right then and there. If it's an old question, it might be months before someone comes across your answer with follow-up questions.