Question

What is the domain of a function like `f(x) = 5x^2`?

Answer 1

The domain is all real numbers. `D:{x:(x=R)}`
Domain is the set of all possible `x` values for a function. The function `y=5x^2` is a parabola graphed below:
graph{5x^2 [-10, 10, -5, 5]}

The function stretches infinitely in both x-directions and is uninterrupted. The y-values (range) are restricted to all numbers greater than zero.