Try to answer the following questions here:

• What is this question used for?
• What does this question assess?
• What does the student have to do?
• How is the question randomised?
• Are there any implementation details that editors should be aware of? ### History and Feedback

#### Checkpoint description

Describe what's changed since the last checkpoint.

#### Chris Graham2 years, 5 months ago

Gave some feedback: Ready to use

#### Chris Graham2 years, 5 months ago

I've renamed the variables to be consistent with the notation used in the question and changed the range of $r$, so that the answer to c) is less likely to be very large.

Published this.

#### Elliott Fletcher2 years, 6 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 6 months ago

Gave some feedback: Has some problems

#### Chris Graham2 years, 6 months ago

Lots of problems with this:

In the question,

• The answer for (b) appears to use the wrong value for a.
• The prompt in (c) asks a term, but then has "common ratio = ..." before the gap.

• I would prefer the table cells to contain the calculation for the common ratio, rather than below, and express as a fraction, e.g. $\frac{-12}{36}=-3$.
• The values for $a_n$ appear to be wrong in the table.
• "Common ratio as..." then seems to give the wrong common ratio (wrong sign at least).

#### Bradley Bush2 years, 6 months ago

Gave some feedback: Needs to be tested

#### Bradley Bush2 years, 6 months ago

Created this.
Geometric Sequence - negative ratio Ready to use Bradley Bush 20/11/2019 14:40
Geometric Sequence - negative ratio draft steve kilgallon 19/11/2017 07:54
Secuencia Geométrica con radio negativo Ready to use Luis Hernandez 14/01/2019 13:21
Geometric Sequence - negative ratio draft Xiaodan Leng 11/07/2019 02:05

Give any introductory information the student needs.

No variables have been defined in this question.

(a number)

Numbers between and (inclusive) with step size
A random number between and (inclusive) with step size

(text string)

(numbers)

(text strings)

This variable is an HTML node. HTML nodes can not be relied upon to work correctly when resuming a session - for example, attached event callbacks will be lost, and mathematical notation will likely also break.

If this causes problems, try to create HTML nodes where you use them in content areas, instead of storing them in variables.

Describe what this variable represents, and list any assumptions made about its value.

This variable doesn't seem to be used anywhere.

Name Type Generated Value

#### Error in variable testing condition

There's an error in the condition you specified in the Variable testing tab. Variable values can't be generated until it's fixed.

Error:

for seconds

Running for ...

No parts have been defined in this question.

Select a part to edit.

The correct answer is an equation. Use the accuracy tab to generate variable values satisfying this equation so it can be marked accurately.

#### Checking accuracy

Define the range of points over which the student's answer will be compared with the correct answer, and the method used to compare them.

#### Variable value generators

Give expressions which produce values for each of the variables in the expected answer. Leave blank to pick a random value from the range defined above, following the inferred type of the variable.

#### String restrictions

Both choices and answers must be defined for this part.

Help with this part type

##### Base marking algorithm

#### Test that the marking algorithm works

Check that the marking algorithm works with different sets of variables and student answers using the interface below.

Create unit tests to save expected results and to document how the algorithm should work.

There's an error which means the marking algorithm can't run:

Name Value

Note
Value Feedback

Click on a note's name to show or hide it. Only shown notes will be included when you create a unit test.

#### Unit tests

No unit tests have been defined. Enter an answer above, select one or more notes, and click the "Create a unit test" button.

The following tests check that the question is behaving as desired.

### This test has not been run yet This test produces the expected output This test does not produce the expected output

This test is not currently producing the expected result. Fix the marking algorithm to produce the expected results detailed below or, if this test is out of date, update the test to accept the current values.

One or more notes in this test are no longer defined. If these notes are no longer needed, you should delete this test.

Name Value

 This note produces the expected output

This test has not yet been run.

When you need to change the way this part works beyond the available options, you can write JavaScript code to be executed at the times described below.

Run this script the built-in script.

This script runs after the built-in script.

To account for errors made by the student in earlier calculations, replace question variables with answers to earlier parts.

In order to create a variable replacement, you must define at least one variable and one other part.

The variable replacements you've chosen will cause the following variables to be regenerated each time the student submits an answer to this part:

These variables have some random elements, which means they're not guaranteed to have the same value each time the student submits an answer. You should define new variables to store the random elements, so that they remain the same each time this part is marked.

### Parts

Give a worked solution to the whole question.

### Preamble

This script will run after the question's variable have been generated but before the HTML is attached.
Apply styling rules to the question's content.

This question is used in the following exams: