Recent content by SopwithCamel

If one uses the limit definition of a derivative (lim of (f(x)-f(a)) / (x-a)) as x approaches a) on a function and you get a value (ie. it is not undefined) does that mean the derivative of the function at that point exists? In other words, even if the limit definition of the derivative works...

I have been working on a slightly tricky calculus problem and was hoping someone could verify my solution. Homework Statement A 4m long beam whose mass is 5 kg is attached to the wall by a wire and a hinge that allows the beam to rotate. There is a sign (with a mass of 20 kg) attached to...