Found this incredible function on my Fx991EX if you press shift and Option button on left corner it creates a QR code that can be scanned with a phone to see graphing
Quick Start Guide | CASIO
Casio Scientific Calculator fx-991ex / fx-991ES PLUS / fx-991MS / fx-82ES PLUS | eBay
Show a Trigonometry Graph transformation on your mobile device via QR codes fx-991EX Casio Classwiz - YouTube
Got ahold of a Casio fx-991ex and CG-50 to match my Classpad II. I'm really impressed with them but there is something about the fx-991ex... (see comments) : r/calculators