1A reviewed; other classes took quiz on right triangle trigonometry. Test on trig on 3/17 or 3/18 next week.
Tuesday/Wednesday
Law of Cosines video
2B/3A/3B explored the graphs of sine and cosine over the angles from 0 to 360 degrees and discovered its wave behavior, and looked at applications of trig wave functions in other fields. Then practiced with law of sines and finding unknown angles in non-right triangles.
Homework: Watch video above and take notes on it.
Thursday/Friday
Started with a warm-up covering using the Law of Sines to find an unknown angle. See video here for similar problem.
Then studied the Law of Cosines and developed a problem solving procedure:
1. Is the shape a right triangle? If so, then use SohCahToa to find missing parts.
2. If not, then try to use the Law of Sines, which requires a complete pair of angle and opposite side.
3. If a complete pair is not given, then the last option is to use the Law of Cosines.
We did an example of how to use the law of cosines to find a missing side. See white board notes here. Here is a video example.
Then, we did an example of how to use the same law of cosines to find a missing angle; that is, how to solve an SSS triangle. These are the hardest types of trig problems in geometry. The white board notes above give how to do it, as does this video (slightly different, but still helpful): link
Homework: selected problems on back of worksheet/notes. Trig Test is Tues/Wed! We will review on Monday.
Resources: Law of Cosines tutorial
When to use the trig rules