Test #3 will be given in class next Thursday, May 10. It will cover sessions 18-25 of the schedule (all of trigonometry).

Webwork TrigEquations has some questions about principal roots where it will accept one answer only. This differs a little from what we called principal roots in class. You can look at section 6.2 for a detailed explanation about what makes a root principal (the ranges for the angles depend on which inverse trig function you’re using). Don’t worry too much about the exact definition of principal root for now; I won’t ask you for them using this language on next week’s test. For Webwork, you can use your calculator’s inverse trigonometric function button and for the most part, it will give you the principal root that you can enter. Webwork still might not accept your calculator’s answer for #5, but there will be only one other candidate root in $[0,2 \pi)$ and Webwork will accept that one.

Here is the Law of Sines animation from today’s class. You can play with it to see that the SSA case might be ambiguous when you’re using the Law of Sines to find an angle.

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