Linear Algebra

Study of vectors, matrices, and linear transformations.

Basic Concepts

Vectors and Their Operations

What are Vectors?

Vectors are mathematical objects that have both magnitude and direction. Imagine arrows pointing in a particular direction with a certain length—those are vectors! They are commonly written as ordered lists of numbers, like \( \vec{v} = (3, 4) \).

Operations on Vectors

You can add two vectors by adding their corresponding components. You can also multiply a vector by a number (called a scalar) to stretch or shrink it.

  • Vector Addition: \( (a_1, a_2) + (b_1, b_2) = (a_1 + b_1, a_2 + b_2) \)
  • Scalar Multiplication: \( k(a_1, a_2) = (k a_1, k a_2) \)

Why Are Vectors Useful?

Vectors are everywhere! They're used to describe forces in physics, directions in navigation, and much more.

Practice Problems

  • Add the vectors \( (1, 2) \) and \( (3, 4) \).
  • Multiply the vector \( (2, -1) \) by \( 3 \).

Examples

  • Adding \( (2, 3) \) and \( (4, 1) \) gives \( (6, 4) \).

  • Multiplying \( (5, -2) \) by \( 2 \) gives \( (10, -4) \).

In a Nutshell

Vectors have both magnitude and direction, and we can add or scale them.

Key Terms

Vector
An object with both magnitude and direction, usually represented as an ordered list of numbers.
Magnitude
The length or size of a vector.
Scalar
A single number used to scale a vector.