Calculator Tips

This page contains information about how to use various calculators for different classes.

Complex Numbers

TI 83, 84, and 89 are all capable of dealing with complex numbers, but in different ways.

Storing Values

If you are asked to perform complex calculations, you may want to store element values so that you can simply type a letter versus entering a number every time you use those values. For example, if a problem asks you to calculate the value of:

\( \begin{align} \Bbb{H}(j\omega)=\frac{j\omega L}{j\omega L + R}\\ L=1\mbox{mH}, R=5\mbox{k}\Omega \end{align} \)

for a few different values of \(\omega\) (say, 10 rad/s and 100 rad/s), you could do the following on your calculator:

1e-3 STO> ALPHA l
5e3 STO> ALPHA r

To store the frequency component, on TI 83/84 plus, you will need to use ALPHA z, while on the TI 89 you can just use the z button:

10 * 2ND i STO> (ALPHA) z

to store the values. Then, to calculate the first value,

( (ALPHA) z * ALPHA l ) / ( (ALPHA) z * ALPHA l + ALPHA r )

Once you get the result, if you want to calculate the value for a different frequency, simply type

100 * 2ND i STO> (ALPHA) z

then use the arrow buttons to go back up to where you performed the previous symbolic calculation, ENTER it to duplicate it, then ENTER it again to calculate.

TI-83/84

Not as many built-in functions for vectors / matrices. See http://www.tc3.edu/instruct/sbrown/ti83/vecprod.htm for a program that will help with cross products.

TI-89

Vectors in General

Vectors may be entered surrounded by [ ]. That is, for some vector \(\vec{r}\):

\( \begin{align} \vec{r}&=r_x\hat{\imath}+r_y\hat{\jmath}+r_z\hat{k} \end{align} \)

say,

\( \begin{align} \vec{r}&=3\hat{\imath}-2\hat{\jmath}+6\hat{k} \end{align} \)

the TI version of the vector would be:

[3, -2, 6]

Note that the result will actually be surrounded by two sets of square brackets, representing a matrix. Be sure to use the unary negative operator (-) versus the binary subtraction operator - at the start of negative entries.

Dot and Cross Products

• Vector operations on TI Calculators: www.phys.lsu.edu/classes/spring2010/phys1100/TI_calc_vec.pdf

Unit Directions

• To find the unit direction for a vector, use
  • <2nd>--<5>MATH--<4>Matrix--L:Vector ops--<1>unitV()

Coordinate Angles

• To find the coordinate angles of a vector, you should first get the unit direction vector. Then, you must turn the unit direction vector into a list before taking the arccos of the list. Lists are surrounded by {} instead of []. To convert a vector to a list, use
  • <2nd>--<5>MATH--<3>List--F:mat->list()
    and put the desired matrix in as the argument; the result will be surrounded by {}. You can then apply the arccos to the list and get all three coordinate direction angles at once!

Questions

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