Show that (x^3+2x)/(2x+1) is Big O(x^2)?

Answer 1

f is a big O of g in a if f/g is limited when x approaches a

(x³ + 2x)/(2x + 1) is O(x²) to the infinity because (x³ + 2x)/(x²(2x + 1)) approaches 1/2 when x approaches infinity