i mean all you need for that is what is a rational or irrational number, if hes not allowed to use that shouldnt be asking a question requiring its definition to be used
If someone askes such a silly question as a sequence of rational numbers that converge to an irrational one, no one is stop you from defining a sequence $a_n =$ the first n terms of root 2, each number is rational and the limit is obviously root 2.
@obliv if the set is bounded, just take the closure of the interval of the upper and lower bound, that is a closed set which contains every element of $a_n$ including a.
i genuinely tried everything and eventually chose to change what i wanted to do based on what i enjoyed doing the most, but yes clearly a cognitive bias i didnt know i had.
@Jakobian My undergrad degree was in physics and biochemistry, i also took classes in psychology, philosophy and statistics. Oddly the only ones i didnt like where classes in statistics, analysis and well PDE's cause who the hell likes pdes.
I find it amazing that you can claim to have more knowledge about someone you just met than a person who has known them for the duration of that persons life.
to employ a logical reasoning of selecting things that i more likely to find enjoyable to learn is in no way a means to pat myself on the back. Its just common sense.
@Jakobian the choice was not made because i wanted to avoid anything applied, it was a result of my not enjoying the things that i learned that were particularly applicable outside of mathematics