but can anyone give me the complete answer for the question 10^n+1 + 3.10^n + 5 is a multiple of 9, ∀n ∈ ℕ
yup I'm a university student. there are no discrete math books available in the library. i searched for pdfs but the explanations are very complicated. while doing a question my lecturer sometimes thinks he is doing it wrong and then stops for a while to try to understand it himself. After which he would try to explain it to a now totally confused class.