allow me to draw graphs, lines, curves such as parabolas, set intervals with sliding bars etc.
I have tried geogebra but it is very limited and is a pain to use. For example, you cannot set a line to have a particular gradient, you can only draw a line and then measure the gradient afterward. And to plot parabolas, you cannot plot equations but rather do it in a microsoft paint style.
Desmos is an excellent graphing calculator, it's very easy and intuitive to use. It also implements derivatives and, since the last update, integrals too.