Area in polar exploratory tool bugs

This tool is light on sanity checks on inputs. For instance, if you choose an interval in θ of length greater than 2π, or an interval of length greater than π paired with a radius function which fails to be non-negative, then the results may not be meaningful. The onus is on the user to choose reasonable inputs.

Some updates are made to displayed formulas on input changes prior to clicking the Process new equation button, while graphical updates are performed only after the button is clicked. This is potentially confusing in some situations.

A definite integral representation for the exact value of the area of the defined region is displayed, but no attempt has been made (yet) to implement an exact computation of this integral even in cases where the integral is elementary. The interested user is encouraged to use a CAS to compute these integrals in select cases and compare with the approximations produced by the tool.