TI-89 CALC error?

[TrueTears]

Eh I typed "solve(sin(3x) = -1 ,x) | "

And it only comes up with ?

But surely is also a solution?

Is my calc broken?

[shinny]

CAS's aren't perfect. This will happen quite often (although I'm surprised it happened on a simple trig equation) and really, the only way to prevent it is to graph everything instead, and find the x intercepts.

[Gloamglozer]

Are you using v 3.10 or v 3.01?  Check by pressing F1 in home and scroll down to "About".

[TrueTears]

CAS's aren't perfect. This will happen quite often (although I'm surprised it happened on a simple trig equation) and really, the only way to prevent it is to graph everything instead, and find the x intercepts.

Yeah I normally do but I was surprised that it got such a simple trig equation wrong... so I thought something must have gone wrong.

Are you using v 3.10 or v 3.01?  Check by pressing F1 in home and scroll down to "About".

Says version 3.10

[Gloamglozer]

Are you using v 3.10 or v 3.01?  Check by pressing F1 in home and scroll down to "About".

Says version 3.10

That should be ok then.  I highly doubt it's going to happen to you, but just to check, your calculator is set to degrees mode, yeah?

If so, then as shinny stated above, the calculator cannot be trusted. 

[pHysiX]

CAS's can be sooooo deceiving. Man, i had the function [latex]\sqrt{x^3-1}[/latex] and i needed values at 2, 2.5, 3, 3.5 and 4. I did this 10 times: y1(....) where y1(x) is the function. The first 3 times, i got different values. The next day, i did it again and got even more different values and for the last 4 times i did it at uni, i was so p'd off that i just took my friend's values...sorry for rambling but yes, being too reliant on CAS is "no good" (cost me my spesh sac >.>)