2022 Spring | Trig

Course Coordinator:
- Nagy
- His webpage here
- Textbook here
Recitation Instructor:
- Winston Cheong
- winstonc@ksu.edu
- Zoom personal meeting room

Recitation Notes

Recit 5 (Feb 15, 2022) We covered material on HW 3: equation of a circle, bearing notation, linear equations "lines", vector arithmetic, unit circle.
- Addendum Feb 16, 2022: Added additional approach for #1 that students informed me of.
Recit 6 (Feb 22, 2022) We covered material on HW 4: evaluating trig functions over the entire unit circle, verifying trig identities, and disproving "false identities".
Recit 7 (Mar 01, 2022) We reviewed for Midterm 2: primarily went over the extra practice problems (verifying trig identities, transforming an angle to different quadrants).
- For additional practice with verifying trig identities:
  - Exercises at the end of Section 2.3 in Nagy's textbook.
  - OpenStax Precalc 2e > Section 7.1: Solving Trigonometric Equations with Identities (Try working through the examples and exercises).
Recit 8 (Mar 8, 2022) We covered material on HW 5: Reading off the equation of a sinusoidal function from its graph, the process for sketching a sinusoidal function.
- The formulas and step by step process are written out in my formula sheet / notes (see below)
- Related Desmos link
- Addendum to recit notes: Explicit calculations going from General Sinusoid to its standard form
- For additional practice with doing arithmetic with fractions:
  - Tyler Wallace's online textbook, Section 0.2.
  - Blackpenredpen's video "100 Fractions"
Recit 9 (March 22, 2022) We covered material on HW6: Evaluating trig(inverse_trig()) and inverse_trig(trig()), finding solutions to elementary trig equations.
Recit 10 (March 29, 2022) We covered material on HW7: Solving more complicated trig equations, dot product and skew product, vector geometry problems, turning angle and geometric angle.
- Additional practice with solving trig equations (with worked solutions): https://tutorial.math.lamar.edu/Problems/CalcI/TrigEquations.aspx
- Additional unit circle practice (with worked solutions): https://tutorial.math.lamar.edu/Problems/CalcI/TrigFcns.aspx
Recit 12 (April 12, 2022) We covered material on Hw8: Calculating area of paralleogram and triangle using vectors, calculating orthogonal projection, solving general triangles using law of sines and law of cosines.
- Obtuse triangle examples:
  - $a=15,\ b=7,\ c=9$
  - $a=20,\ b=5,\ \widehat{C} = 5^\circ$
Recit 13 (April 19, 2022) We covered material on Hw9: Area of triangle giving side/angle info, problems involving sum/difference formulas for sine/cosine/tangent.
Recit 14 (April 26, 2022) We covered material on Hw10: Problems involving double-angle, half-angle, product-to-sum, and sum-to-product formulas.
Recit 15 (May 3, 2022) We covered material on Hw11: Converting representations of complex numbers, using De Moivre's formula for powers and roots of complex numbers, finding all roots (real and complex) of a polynomial.

Videos

Trig resources

My unit circle cheatsheet here. Source available here.
My formula sheet / notes for this course here. Source available here.

Other Resources

Paul Dawkins (Lamar U) > Cheatsheets
- Has algebra, trig
Tyler Wallace's Beginning and Intermediate Algebra textbook here
- Has good problems, and many solutions