# Activities

• ##### Download

• • ##### Subject Area

• Math: Precalculus: Other Topics: Matrices, Sequences, and Series

• ##### Author 9-12

45 Minutes

• ##### Device
• TI-Nspire™ CX/CX II
• TI-Nspire™ CX CAS/CX II CAS
• TI-Nspire™ Navigator™
• TI-Nspire™
• TI-Nspire™ CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

3.0

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Cryptology and Matrices

#### Activity Overview

This lesson involves using matrices to encode and decode a message.

#### Objectives

• Students will use their knowledge of matrices and their inverses to encode and decode messages, solve systems of equations, and write equations for messages.
• Students will be able to input their data into matrices and perform calculations on them.
• Students be able to interpret the results of their calculations.
• Students will utilize different methods to check the results of their calculations and verify their solutions.

#### Vocabulary

• decode
• determinant
• encode
• identity matrix
• inverse matrix
• matrix

#### About the Lesson

This lesson involves using matrices to encode and decode a message.
As a result, students will:

• Learn how matrices can be applied to real world problems.
• Learn that (some) matrix multiplications can be "undone" by multiplying by an inverse matrix.