Write the symbolic diff function
Example:
4*x^3, x //=> 12*x^2
4*x^3, y // => 0
4*x^3-x^2, x //=> 12*x^2 - 2*x
Allowed operations are +, -,* and ^.
The program has to handle polynomials, other functions are optional.
Any other operation should lead to an error.
Use TDD!
Implement minimalistic UI: input field, resulting text and a button to run it.