I was leafing through the beginning pages of my Calculus book and just found something that kind of boggles me, a simple domain and range problem that I just don't get. (Problem below momentarily.)

Question

mendicant_bias · Answer

The short bit of the problem that I care about is finding the domain and range of f(x), where f(x) = x. The thing that seems strange is the answer given for the domain is $$D _{f} : -\infty < x < \infty $$

mendicant_bias · Answer

But, this seems odd; why is it that, as opposed to $$D _{f}: (-\infty , \infty)$$?

mendicant_bias · Answer

Oh. Wait a sec...is this just different notation for the exact same thing?

mendicant_bias · Answer

*And even if* that is the case, why the different notation? Is this kind of like how we use the obelus and two others primarily (can't remember the name) to represent division?

ganeshie8 · Answer

yep both notations represent same thing. the second one is in interval notation, while the first one is inequality

mendicant_bias · Answer

That's really odd. I apparently totally forgot that inequalities were used to represent ranges. Thanks.

ganeshie8 · Answer

good luck with ur revision wid calculus !