Find the maximum and the minimum values, if any, without using derivatives of the following functions: `f(x)=2x^3+5` on `R`

Explanation

Neither maximum nor minimum value exist for the given function f(x) as

`x ^3 →∞ for x→∞ and x ^3→−∞ for x→−∞`

So, f(x)→∞ for x→∞ and

f(x)→−∞ for x→−∞