TI-nspire cx CAS Calculator-HELP PLEASE

[Sarah P]

So i've been going through circular functions and my CAS calculator is not giving me the correct answer! I've been typing 12*sin(30) and it keeps on giving me -11.856. But when I put the same equation into my TI-30XB MultiView by Texas Instruments, it gives me the correct answer of 6.

Can someone please tell me why my CAS calculator is doing this and how I can change it? Any help is much appreciated.

[MightyBeh]

So i've been going through circular functions and my CAS calculator is not giving me the correct answer! I've been typing 12*sin(30) and it keeps on giving me -11.856. But when I put the same equation into my TI-30XB MultiView by Texas Instruments, it gives me the correct answer of 6.

Can someone please tell me why my CAS calculator is doing this and how I can change it? Any help is much appreciated.

That's pretty odd - could you tell me (us? ) what's on your document settings page?
Should be something like this:

Spoiler

Float
Radian
Normal
Real
Exact
Rectangular
Decimal
SI

Edit: Wait, I got it. If you want 6 you have to specify that you're working in degrees. There's a degree symbol in the pi menu if you don't feel like switching back and forth in the document settings all the time. You get -11.856... if you don't set this because it looks like radians is your default setting, so it's calculating 30 radians instead of 30 degrees.

[zsteve]

So i've been going through circular functions and my CAS calculator is not giving me the correct answer! I've been typing 12*sin(30) and it keeps on giving me -11.856. But when I put the same equation into my TI-30XB MultiView by Texas Instruments, it gives me the correct answer of 6.

Can someone please tell me why my CAS calculator is doing this and how I can change it? Any help is much appreciated.

Your calc is in radian mode, tried it on mine 12sin(30)=-11.856... (sin of 30 rads).
Don't change it back to degrees - I'd recommend you keep your calc set on rads as it's very easy to walk into an exam/SAC with the calc set on degrees and then get the whole thing wrong ... it's a fairly common incident according to examiner's reports.
Instead, I would define dg = 180/pi and rd = pi/180
Then, to find 12sin(30 deg), I'd type
12sin(30*rd) - multiplying anything by 'rd' converts it from degrees to radians, multiplying anything by 'dg' converts it from radians to degrees.
That's how I used my calc through year 12 anyway. I never used degrees mode

[Sarah P]

Your calc is in radian mode, tried it on mine 12sin(30)=-11.856... (sin of 30 rads).
Don't change it back to degrees - I'd recommend you keep your calc set on rads as it's very easy to walk into an exam/SAC with the calc set on degrees and then get the whole thing wrong ... it's a fairly common incident according to examiner's reports.
Instead, I would define dg = 180/pi and rd = pi/180
Then, to find 12sin(30 deg), I'd type
12sin(30*rd) - multiplying anything by 'rd' converts it from degrees to radians, multiplying anything by 'dg' converts it from radians to degrees.
That's how I used my calc through year 12 anyway. I never used degrees mode

That's pretty odd - could you tell me (us? ) what's on your document settings page?
Should be something like this:

Spoiler

Float
Radian
Normal
Real
Exact
Rectangular
Decimal
SI

Edit: Wait, I got it. If you want 6 you have to specify that you're working in degrees. There's a degree symbol in the pi menu if you don't feel like switching back and forth in the document settings all the time. You get -11.856... if you don't set this because it looks like radians is your default setting, so it's calculating 30 radians instead of 30 degrees.

Thank you both so much for the help! As I always use scratchpad for my calculations, changing the settings to degrees doesn't seem to affect the result (as it only appears to work whilst in a new document). All that I have to do now is remember to add pi/180 to my calculations to get the degrees/correct answer!  Seriously though, you guys are saints, thank you!

[MightyBeh]

Thank you both so much for the help! As I always use scratchpad for my calculations, changing the settings to degrees doesn't seem to affect the result (as it only appears to work whilst in a new document). All that I have to do now is remember to add pi/180 to my calculations to get the degrees/correct answer!  Seriously though, you guys are saints, thank you!

If you change your document settings then press 'set as default' it should work in the scratchpad, and any other document. 

[Sarah P]

If you change your document settings then press 'set as default' it should work in the scratchpad, and any other document. 

Oh OK that seems to work a lot better, thank you!