[scheduled:: 2025-01-14]

Trigonometric Functions

Links and useful resources

• gr10's Geometry >>>START HERE<<<
• AoPS Alcumus
• Handwritten math converter
• Big Ideas Geometry textbook
• GeoGebra Online Geometry Constuction Tool
• Two-column math templates
• Proofs unit slides from mathgiraffe.com
• Proofs unit printables for two-column proofs

Lesson-specific resource links

• Trigonometry intuition from BetterExplained
• reddit thread - what are sin/cos/tan?
• The law of sines
• The law of cosines
• Wikipedia list of trig identities
• GeoGebra Exploring triangle identities

Concept summary and connections

• SOH-CAH-TOA
  • Sine - opposite over Hypotenuse
  • Cosine - Adjacent over Hypotenuse
  • Tangent - Opposite over Adjacent
• sine cosine tangent
• Inverse functions: arcsine arccosine arctangent
• trigonometric identities (demonstrate in class)
• #quiz What is another way to express $\sin (90-x)$
• #quiz What is the Law of Sines: $\frac{a}{\sin (A)}=\frac{b}{\sin (B)}=\frac{c}{\sin C}$
• #quiz What is the Law of Cosines: $c^2=a^2+b^2-2ab\cos C$
• #quiz Solve a triangle using the law of sines (examples)
• #quiz Solve a triangle using the law of cosines (examples)

Worked examples

• $(\sin x{)}^2+(\cos x{)}^2=1$
• $\frac{\sin x}{\cos x}=\tan x$

Media resources

• Youtube search for "sine"
• Youtube search for "cosine"
• Youtube search for "tangent"
• Youtube search for "arcsine"
• Youtube search for "arccosine"
• Youtube search for "arctangent"
• Youtube search for "trigonometric ratios"
• Youtube search for "trigonometric identities"

Guided practice

• what is $(sin(x){)}^2+(cos(x){)}^2$
• what is $\frac{sin(x)}{cos(x)}$?

Homework

• #hw (geom-gr10) (class notes) DO IN CLASS during prealgebra: IXL trig practice 2025-01-14