# Determinants of 3x3 matrix on approved calc?



## dzdave00 (Mar 11, 2008)

Hi all, I am studying for the PE electrical in April, and while working through basic electrical circuit analysis for the second time, I noticed that it was taking a long time to work out solutions to 3 linear equations with 3 unknowns using Cramers rule (with which I am most comfortable). Is there a way to calculate determinants using any of the approved NCEES calculators and reduce the time required to do this simple, but time consuming step? I have the TI 30XA now only because I had one laying around, but would switch in a heartbeat to something else if it could do this.

I normally use a TI 86 for everyday calcs. Thanks!


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## Dark Knight (Mar 11, 2008)

dzdave00 said:


> Hi all, I am studying for the PE electrical in April, and while working through basic electrical circuit analysis for the second time, I noticed that it was taking a long time to work out solutions to 3 linear equations with 3 unknowns using Cramers rule (with which I am most comfortable). Is there a way to calculate determinants using any of the approved NCEES calculators and reduce the time required to do this simple, but time consuming step? I have the TI 30XA now only because I had one laying around, but would switch in a heartbeat to something else if it could do this.
> I normally use a TI 86 for everyday calcs. Thanks!


The Casio FX-115ES can handle that, I think.

On a more realistic note, I do not think you will have to deal with that on the test. Maybe a 2x2, but not a 3x3.


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## Katiebug (Mar 11, 2008)

dzdave00 said:


> Hi all, I am studying for the PE electrical in April, and while working through basic electrical circuit analysis for the second time, I noticed that it was taking a long time to work out solutions to 3 linear equations with 3 unknowns using Cramers rule (with which I am most comfortable). Is there a way to calculate determinants using any of the approved NCEES calculators and reduce the time required to do this simple, but time consuming step? I have the TI 30XA now only because I had one laying around, but would switch in a heartbeat to something else if it could do this.
> I normally use a TI 86 for everyday calcs. Thanks!


The Casio fx115-ES will do matrix operations up to 3x3. I really like the Casio, much better than the TI-30XS that I was using before.

If you use a TI 86 you will probably be pleasantly surprised by the Casio. It's a nice little calculator.


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## dzdave00 (Mar 11, 2008)

Thanks a lot. I'll probably get the Casio, as I want to bring in two working calculators to the test.


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## roadwreck (Mar 11, 2008)

dzdave00 said:


> Thanks a lot. I'll probably get the Casio, as I want to bring in two working calculators to the test.


I've been a higher end TI user ever since high school, so I bought the TI-36X for the exam and bought the Casio as my backup. While studying I found I much preferred the Casio and it's become my everyday calculator. I've got it sitting here on my desk now.


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