# Book Extras: Principles of Algebra 2

### Helpful Resources

• Free Online Graphing Calculators – These calculators can be used instead of a graphing calculator for this course. (It is recommended that college-bound students get a graphing calculator, however, so they are already familiar with using one.)
• Desmos (suggested, due to ease of identifying values and zooming in and out) – Note that you have to press the keyboard symbol in the bottom left to get a keyboard. Press y = and the values y equals, using x to stand for the independent variable. Use ^ to show exponents (use your right arrow to get back from an exponent to a regular value). Click on the graph of the curve itself to see the value at any particular point. Zoom in or out using the plus or minus signs. Add a second equation by clicking underneath where the first is typed and typing another one.
• Math Is Fun – Use ^ to show exponents; use the first line for inputting the first equation, and the second for the second.
• Free Online Matrix Calculators – These calculators can be used to calculate matrices.
• Desmos – Input a new matrix for each matrix. Press A, A^-1, B to find (A^-1)(B).
• Math Is Fun – Note that in order to calculate (A^-1)(B), you have to first press “inv(A)”, and then press the “to A” button in order to store it as Matrix A. Then press the AB button to calculate A times B, which is really (A^-1)(B), as you stored A^-1 as A (A^-1 is another way of saying the inverse of A).
• The Atheist Delusion – Watch free online or order a DVD.