This could be a trivial question, but what is exactly the difference of between these two expressions? Am I correct to state the both interchangeably whenever I need to express the approximation of pi? I'm bit confused as here it states pi can be express by ≒ as it's not a rational number, but pi can also be expressed by a series (asymptotic), so it should be ≈ as well.
π ≈ 3.14..
π ≒ 3.14..

