Recap: Geometric Sequences

Part of the Exponentials, Logs & Sequences section of Coddy's Algebra 2 journey. Lesson 44 of 49.

Challenge

The sequence 80, 40, 20, ... has the rule a(n) = 80 × (1/2)^(n - 1). Work out a(5). Tap the move that uses the rule, then type the arithmetic line by line.

Try it yourself

a(5)

Simplify the expression

All lessons in Exponentials, Logs & Sequences

1Exponential Functions

Repeated Multiplying Growth or Decay Drawing Growth Drawing Decay Recap: Exponential Functions

4Meet the Logarithm

What a Log Is Reading a Log Logs of Fractions From Log to Power Recap: Logarithms

7Log Equations

Combine, Then Undo A Difference of Logs Same Log Both Sides A False Answer Recap: Log Equations

10Final Challenges

Final: Same Base Final: Log It Final: Two Logs Final: The Investment Final: The Staircase

2Growth and Decay

Doubling Halving Growing by a Percent Losing a Percent Recap: Growth and Decay

5Log Rules

The Product Rule The Quotient Rule The Power Rule Into One Log Recap: Log Rules

8Arithmetic Sequences

The nth Term Which Term?Adding the Terms Recap: Arithmetic Sequences

3Same-Base Equations

Matching Powers Rewriting the Base An Expression Upstairs Fractions and Negatives Recap: Same Base

6Solving with Logs

Take the Log Isolate the Power First Base e Undoing ln Recap: Solving with Logs

9Geometric Sequences

Multiply Each Time Finding the Ratio Geometric Sums Forever SumsRecap: Geometric Sequences