Math Notes

My personal collection of mathematics notes, examples, and explanations.

Note Entries

Trigonometric Functions

Trigonometric Functions

In the unit circle, we can visualize the relationship between sine and cosine functions. For any angle θ:

  • sin(θ) represents the y-coordinate
  • cos(θ) represents the x-coordinate
  • The fundamental identity sin²(θ) + cos²(θ) = 1 is derived from the Pythagorean theorem

$$\sin^2 \theta + \cos^2 \theta = 1$$

SOH CAH TOA

SOH CAH TOA Trigonometric Mnemonic

SOH CAH TOA is a mnemonic device to remember the trigonometric ratios for right triangles:

  • SOH: Sine = Opposite / Hypotenuse
  • CAH: Cosine = Adjacent / Hypotenuse
  • TOA: Tangent = Opposite / Adjacent

Area of Triangles

Triangle Area Calculation

Learn different methods to calculate the area of triangles, including:

  • Standard formula: A = ½ × base × height
  • Area of right-angled triangles
  • Area of equilateral triangles
  • Area of isosceles triangles
  • Heron's formula for any triangle

Solids of Rotation

Solids of Rotation

Learn how two-dimensional shapes can be rotated around an axis to create three-dimensional objects:

  • Understand the concept of solids of rotation
  • Explore common shapes like cylinders, cones, and spheres
  • Learn volume formulas for various solids
  • See how calculus is applied to calculate complex volumes
  • Study advanced examples and interactive demonstrations

Geometric Dilations

Geometric Dilations

Master geometric transformations that change size while preserving shape:

  • Understand scale factors and centers of dilation
  • Calculate area changes with k² scaling relationship
  • Determine scale factors from given areas
  • Apply dilations to solve real-world problems
  • Work with enlargements and reductions

Density and Volume Relationships

Density and Volume

Explore the fundamental relationship between mass, volume, and density:

  • Master the density formula: Density = Mass/Volume
  • Convert between different units (g/cm³, kg/m³)
  • Calculate any variable when given the other two
  • Apply density concepts to real-world problems
  • Understand density as an intrinsic property

Volume Calculations of 3D Solids

3D Volume Calculations

Calculate volumes of various three-dimensional geometric solids:

  • Cylinders: V = πr²h or V = B×h
  • Cones: V = (1/3)πr²h
  • Pyramids: V = (1/3)×BaseArea×h
  • Prisms: V = BaseArea×h
  • Spheres: V = (4/3)πr³