# Trigonometry

## Concept Learning Sessions

Session # 1 Angle Measure: Sexagesimal System, Centesimal System, Circular Measure

Session # 2 Theorem: The ratio of the circumference and the radius of a circle is a constant.

Session # 3 What is pi? The session discusses the approximate value of pi and various expressions (definite integrals, continued fractions) whose value is equal to pi. Also, it discusses the method of finding approximate values of pi using continued fraction.

Session # 4 Trigonometric Ratios - 1: Using a unit circle the definition of the 6 T-ratios has been explained using Geogebra tool.

Session # 5 Trigonometric Ratios - 2: Change in the value of T-Ratios with the change in the value of angle. T-Ratios are dependent on angle - demonstrated through Geogebra tool.

Session # 6 Trigonometric Ratios - 3: T-Ratios depend only on the angle and not on the side-lengths of a right angled triangle.

Session # 7 Trigonometric Identities: FUNDAMENTAL RELATIONS BETWEEN T-RATIOS - 1

Session # 8 Trigonometric Identities: FUNDAMENTAL RELATIONS BETWEEN T-RATIOS - 2

Session # 9 Trigonometric Identities: FUNDAMENTAL RELATIONS BETWEEN T-RATIOS - 3

Session # 10 Limits to the values of Trigonometric Ratio. Ranges of the values of T-Ratios

Session # 11 Expressing T-ratios in terms of other T-ratios. In this session one example problem has also been taken to express all the T-ratios in terms of Sine value.

Session # 12 Values of T-ratios of some specific angles - 1. Derivation of values of T-Ratios for 0 and 90 degrees using Geogebra tool

Session # 13 Values of T-ratios of some specific angles - 2. Derivation of values of T-Ratios for 45 degrees using Geogebra tool

Session # 14 Values of T-ratios of some specific angles - 3. Derivation of values of T-Ratios for 30 and 60 degrees using Geogebra tool

Session # 15 Complementary Angles and their T-Ratios

Session # 16 Application of Trigonometry: Angles of Elevation and Depression

## Demonstration Sessions

Session # 1 This video uses Geogebra tool to show that Trigonometric Identities do not depend upon the angle and they hold for all values of the angle

## Problem Solving Sessions

Session # 1 Sector Angle = Arc Length/Radius. To find the diameter of the Sun, if the average distance between the Sun and Earth and the angle subtended by the Sun's Diameter on an observer's eye standing on earth are given.

Session # 2 Trigonometric Identities: Problem based on Trigonometric Identity

Session # 3 Trigonometric Identities: Problem based on Trigonometric Identity

Session # 4 Trigonometric Identities: Problem based on Trigonometric Identity

Session # 5 Trigonometric Identities: Problem based on Trigonometric Identity

Session # 6 Trigonometric Identities: Problem based on Trigonometric Identity

Session # 7 Expressing T-ratios in terms of the other T-Ratios and solving a quadratic equation based on that

Session # 8 Problem on Heights and Distances (application of Trigonometry)

Session # 9 Finding the height of a tower when the angle of depression of the top and the bottom of the tower have been given from a cliff of given height.

Session # 10 Heights and Distances: Finding the height of a tower when angle of elevations are in two different planes.