# Vector algebra: Some exciting applications

**What is this session about**

###### Vector algebra made interesting

*Concepts from vector algebra are introduced at the higher secondary level. If we show students how it helps answer some interesting questions from diverse fields, they will find it more interesting.*

**Elegant solutions**

*Vector algebra can lead us to short and elegant proofs/solutions, when used in conjunction with ideas like symmetry*

## What do we discuss in this session?

Here we look the** applications of vector algebra** to answer some questions from trigonometry, geometry, chemistry and astronomy.

- Applying vector algebra to derive some trigonometric results in a simple manner
- An everyday example of finding the angle between pipes on perpendicular faces of a building
- The structure of a molecule like methane, using symmetry arguments
- Addressing misconceptions about phases of the Moon using a more involved application of vector algebra

00:00 Introduction

05:21 Dot product to prove trigonometric angle addition formula

09:45 Cosine rule

15:45 Angle between two pipes along two faces of a building

18:07 Is the angle between planes same as the angle between lines in those planes?

27:15 Angles in a tetrahedral Methane molecule

41:00 Explaining phases of the Moon with vector algebra