Trigonometry

The Study of Space

Page 1: Introduction to Trigonometry

  • Definition of Trigonometry

    • A branch of mathematics focused on the relationships between the sides and angles of triangles.

    • Literally translates to "study of triangles."

Page 2: Etymology

  • Origin of the Term

    • Derived from Greek: "trigon" (triangles) and "metron" (measurement).

Page 3: Applications of Trigonometry

  • Astronomy

    • Triangulation Technique: Used to measure distances to nearby stars.

  • Civil Engineering

    • Force Distribution: Engineers calculate forces in structures like truss bridges.

    • Angle Calculations: Determining angles and lengths of beams.

  • Navigation

    • Satellite Navigation: Essential for pilots to know angles for takeoff and turns.

  • Architecture

    • Building Measurements: Used to determine heights and dimensions for structures.

    • Material and Labor Estimation: Helps in planning geometrical patterns and resource requirements.

  • Music Theory

    • Sound Waves: Trigonometry aids in developing computer-generated music through wave patterns.

    • Sine and Cosine Functions: Fundamental in sound engineering.

  • Geography

    • Spherical Trigonometry: Utilized for measuring distances between landmarks and understanding time zones.

  • Higher Mathematics and Sciences

    • Applications in calculus, physics, statistics, biology, and more.

Page 4: Historical Context

  • Hipparchus

    • Known as the "father of trigonometry" for compiling the first trigonometric table.

Page 5: Related Concepts in Trigonometry

  • Angles

    • Defined as the space between two rays sharing a common endpoint (vertex).

Page 6: Parts of an Angle

  • Initial Side: The stationary side of the angle.

  • Terminal Side: The side that rotates to form the angle.

Page 7: Angle Measurement

  • Units of Measurement

    1. Degrees (°)

      • Represents 1/360 of a full rotation.

      • Can be expressed in decimal form for precision.

    2. Radians (rad)

      • Standard unit of angular measure; one radian is just under 57.3 degrees.

      • Defined as the angle subtended by an arc equal in length to the radius.

    3. Gradians (grad, gon)

      • Equivalent to 1/400 of a turn; useful for mental arithmetic.

    4. Angular Mil

      • Used in military contexts; relates to subtension for size and range calculations.

Page 8: Types of Angles

  • Zero Angle: Exactly 0°.

  • Acute Angle: Greater than 0° and less than 90°.

  • Right Angle: Exactly 90°.

  • Obtuse Angle: Greater than 90° and less than 180°.

  • Straight Angle: Exactly 180°.

  • Reflex Angle: Greater than 180° and less than 360°.

  • Full Angle: Exactly 360°; also known as a complete angle or perigone.

Page 9: Notation

  • Greek Letters: Commonly used to denote angles in trigonometry (e.g., θ, α, β).

This note summarizes the key concepts and applications