Hey there!

I hope you are all doing well! (I hope I am posting this in the correct section of the forum )

I am currently moving up to A-level further maths, so I have just moved from an "fx-85GT PLUS" to an "fx-991EX Classwiz", because this is what my school recommends..

The problem is, this CASIO has a serious flaw.

Let us take the following matrix:

Now I want to inverse this matrix (which is worth 1 mark in my text book), so I type it into my calculator:

As one can see, the calculator has lost any knowledge of surds, and has just done the Decimal calculation. Obviously, for 1 mark, doing a full 3x3 matrix inversion in surd form, is not worth it.

So I started to look for a calculator that could do this (I am happy to buy used, I'm in the UK), and so tried emulating other calculators.

The ones that couldn't do it (from my test, off the top of my head):

- FX-9860G

- Ti-83 (This might be sacrilegious to post on here, but it didn't work, so i might as well)

- FX-9750GIII

So I ended up trying, and I realized that the "fx-9860GIII" could do it!

As you can see, it keeps surd form up to this point!

But then boom, you inverse it, and it loses all the surd information .

I wonder if any casio calculator can actually do this properly? Or if I need to look at different companies' calculators?

So my question is, is there maybe an older casio model that can do 3x3 matrix inversions whilst keeping surd form? Or a different company all together?

Or maybe there is a function on the fx-991EX which can do this for us?

I also do love the idea of having a graphing calculator functions, and am a programmer, so I would be interested if these features were available too.

Stay safe and I hope you are all well!

~ James