# How to plot a function with variable with an open interval? [closed]

I want to plot this revenue function: $r=30q-0.3q^2$

I have no range, its an open interval, but when I try to plot in Mathematica it requires the min and max of the plotting limits.

How do I do this?

*Edit: Thank you for helping, my professor gave us the revenue function mentioned up, and asked us to plot " revenue versus quantity (q) ", he did not specify any range, or max and min. My question is can i plot this without a max and min?

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## closed as unclear what you're asking by Sjoerd C. de Vries, Kuba, m_goldberg, Artes, rm -rf♦Dec 10 '13 at 14:21

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

What is commonly known as "open interval" is characterized by min and max. So please clarify or define open interval. –  Kuba Dec 10 '13 at 13:02
Are we here making home works instead of students? –  Alexei Boulbitch Dec 12 '13 at 9:16

r[q_] := 30 q - 0.3 q^2;