Let's steal some issues from https://github.com/davidedc/Algebrite! >:3

### Tests for our future integral implementation
- [ ] 13: 1/x^3*1/sqrt(x^2-4)
- [ ] 15: arccos(x)
- [ ] 16: arctanh, arcsinh, arccosh [Requires hyperbolic functions and their inverses]
- [ ] 17: 1/x [Requires abs function and flag for signifying real variables]
- [ ] 18: x^2/(a+b*x)
- [ ] 19: x*sqrt((-9)-x^2)
- [ ] 22: t^(-1/2)*exp(-t^(-2))

### Tests for our future simplification
- [ ] 35: incorrect simplification of: sqrt(x*y) , sqrt(1/x) , sqrt(x^y)
- [x] 108: Error in simplify() with division and powers: 1 / (( y ^ 2 ) ^ ( 1 / 2 ) )

### New functions
- [ ] 20: summation [Should include product as well]
- [x] 33: How to compare two numbers? [Requires boolean logic]
- [x] 80: Is it possible to find the domain of a function over the reals?
- [ ] 87: Solving equations with modular arithmetic

### Bugs
- [ ] 29: incorrect ordering of function calls
- [x] 99: Simplify call significantly slower for "x^(-6)+1" than for "x^(-6)" [AngouriMath literally hangs for this]

### Tests to add
- [x] 38: simplify (x^2-x*y)/(x*y-y^2)