In Need of Casio Classpad Help!

[paranoidchair]

Hi guys,
I'm having a lot of trouble with my cas when I try to solve questions like these (attached below taken from the 2015 TA VCAA paper https://www.vcaa.vic.edu.au/Documents/exams/mathematics/2015/2015mmcas2-w.pdf).





I've tried multiple methods to get it to work - for example for part b) I've put d in from the variable tab and try to differentiate it and that won't work, I've put d in from the abc tab and that doesn't work, I've tried using different letters and variables and that doesn't work. I've also successfully defined the function using variable d and abc d respectively, but when I try to differentiate it the calc will come up with 'incorrect argument'. I've asked friends on how to do it but they all have a Ti-Nspire which seems to be able to handle these sorts of questions

If someone knows how to get around this, I'd greatly appreciate it! It takes too long to do it by hand and its super easy to stuff up.

Thanks!

[snip]

From what I've found, if a variable is defined as a function the calculator will come up with an error message if you then try to use that same variable in an equation. So basically, if you had a function defined as d(x), I think it won't let you use d as a variable like you would in question b. To fix this you can go to settings and just clear all of your defined functions.
If you don't want to clear your functions, what I often do is go to abc and then αβγ, and use Greek letters as my variables, because I never use them for anything else.

[paranoidchair]

From what I've found, if a variable is defined as a function the calculator will come up with an error message if you then try to use that same variable in an equation. So basically, if you had a function defined as d(x), I think it won't let you use d as a variable like you would in question b. To fix this you can go to settings and just clear all of your defined functions.
If you don't want to clear your functions, what I often do is go to abc and then αβγ, and use Greek letters as my variables, because I never use them for anything else.

Thanks so much! I tried using αβγ and it worked!