Suggestions... But needs to improve!!

Very nice and friendly plotter for 2d, I am evaluating it till this moment. Suggestions as Mathematician

The issues and petitions for next updates:

1)Please incorporate a feature to save/load graphs , this is essential.
2)add the feature to plot x=f(y), for example: x=y^2
3)needs to plot implicit equations: x^2+y^2=25 (circle radius=5)

The good:
Fantastic app, since I ve tried almost all graphers in the store and only few ones has the magnificient feature of plotting derivatives. As math teacher I hope you can take into account my petition . Nice purchase , buy it guys.

RAUL MATHEMATICIAN about Graphicus - Graphing Calculator