Once I was in my calculus class and I had to demonstrate an optimization problem on the board. It was finding the maximum area of a triangle inside a circle with radius r. When I got to the part where I had to differentiate, I said something along the lines of, "the derivative of r*t with respect to t is r, because r is a constant." But when I think about it, r is not a constant, because it is a variable!(adsbygoogle = window.adsbygoogle || []).push({});

So now I am really confused about whether something is a constant or not. Am I correct in saying that r is a constant?

(Sorry if this is in the wrong forum. Even though I used an example from calculus, I'm not sure if this is entirely a calculus topic so I put it in the general section.)

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Constant Variables?

**Physics Forums | Science Articles, Homework Help, Discussion**