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.

#### Christopher boyd1 year, 10 months ago

Gave some feedback: Ready to use

#### Chris Graham2 years, 3 months ago

Gave some feedback: Ready to use

#### Christian Lawson-Perfect2 years, 3 months ago

Gave some feedback: Ready to use

#### Christian Lawson-Perfect2 years, 3 months ago

Saved a checkpoint:

Made sure neither of the points lies on the $y$-axis.

Split $a$ into two parts, since you need to work out the gradient before you find the $y$ intercept.

Reworded some of the advice a bit.

#### Chris Graham2 years, 3 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 3 months ago

This was a bit of a mess, as the points A and B had originally been illogically ordered, and this had only been half fixed.

Part a) had mathematical expression gaps which should have been number entry, and I have added fractionNumbers simplification in the advice and displayed answer.

I've adjusted the axis ranges so that the intercept is always on the grid.

#### Chris Graham2 years, 4 months ago

The points A and B should be switched; it doesn't make sense to describe the leftmost point as B, and in fact the gradient is calculated from A to B in the advice. There are places in the advice where $y_1-y_2$ needs to be inverted.

#### Chris Graham2 years, 4 months ago

Gave some feedback: Has some problems

Published this.

#### Chris Graham2 years, 4 months ago

RE the point below from Aiden, this is OK, it is giving the student the opportunity to explore the terms in the equation and how they relate to the graph. This sort of question is really for formative use.

#### Aiden McCall2 years, 4 months ago

This is also true for all other questions of this nature.

#### Aiden McCall2 years, 4 months ago

Saved a checkpoint:

I have edited the main and advice to make sense and tweaked parts. There is a problem with the question that where you put y = mx +c you can write m in the gap fill and even when restricting the string it shows what m is on the graph so you can effectively 'cheat' this also works in the same way if you type in c. I cannot think of a way to fix this without the JSXgraph code and I don't know where abouts that is.

#### Bradley Bush2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Bradley Bush2 years, 4 months ago

Thank you for the feedback Chris, I have done everything you've suggest4ed here as well as making the same changes to differenet versions of this question.

#### Chris Graham2 years, 4 months ago

One more. If I do not attempt the question, but reveal the answers, then the advice refers to an absent green line. This is another good reason to put the correct plot in the advice.

#### Chris Graham2 years, 4 months ago

Similar points to our earlier discussion:

This is a candidate for using the Numbas variables to set the jsxgraph axis limits. Move the block of code where you grab the Numbas variables in front of making the board, so that you have access to them. And then you can use them in the bounding box definition boundingBox:[yb-2,...] or whatever is sensible. Don't forget you'll want the intercept to be on the board.

Since you are only asking for the equation of the straight line through the points, you might consider creating a step with gapfills for the gradient and intercept, to allow the student to break the question down.

And you could add a second plot with the solution to the advice.

One final thing: on one run I had B at the origin. You may wish to avoid this as it makes parts of the advice obsolete.

#### Chris Graham2 years, 4 months ago

Gave some feedback: Has some problems

#### Bradley Bush2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Bradley Bush2 years, 4 months ago

Created this.
Find the equation of a line through two points - positive gradient Ready to use Bradley Bush 18/06/2018 14:45
Find the equation of a line through two points - negative gradient Ready to use Bradley Bush 16/11/2019 22:03
Find the equation of a line through two points - zero gradient Ready to use Bradley Bush 17/06/2019 11:48
Straight line equation application: measuring sunflower height Ready to use Bradley Bush 09/08/2019 11:11
Christopher's copy of Finding a line equation through two points +ve gradient JSX draft Chris Graham 10/07/2017 18:29
Louise's copy of Find the equation of a line through two points - positive gradient draft Louise Lynch 25/01/2018 22:30
Find the equation of a line through two points - positive gradient draft Mark Hodds 23/02/2018 14:10
Ida's copy of Find the equation of a line through two points - positive gradient draft Ida Landgärds 12/04/2018 14:00
Spørsmål 1 draft Ida Landgärds 19/06/2018 13:40
Marte's copy of Find the equation of a line through two points - positive gradient draft Marte Bråtalien 12/04/2018 14:13
Thomas's copy of Find the equation of a line through two points - negative gradient draft Thomas Strasser 11/05/2018 01:28
Equation de droite Needs to be tested Alain Virouleau 30/05/2019 18:52
Linear Equations - Find the equation of a line through two points draft Paul Hancock 31/07/2018 00:30
Find the equation of a line through two points - positive gradient [L3] Needs to be tested Matthew James Sykes 25/07/2018 11:12
Beer Lambert Law Doesn't work Matthew James Sykes 24/07/2018 15:03
Beer Lambert Law Working Back up Should not be used Matthew James Sykes 25/07/2018 10:35
Joël's copy of Find the equation of a line through two points - positive gradient draft Joël Cohen 27/08/2018 12:26
Beer Lambert Law Working Back up Should not be used Matthew James Sykes 04/09/2018 15:30
Ida's copy of Spørsmål 1 draft Ida Landgärds 23/11/2018 07:54
David's copy of Straight line equation application: measuring sunflower height draft David Rickard 07/11/2018 21:05
equation of a line through two points draft heike hoffmann 14/11/2018 22:49
Equation of a line through two points draft Johnny Yi 14/01/2019 05:38
Equation of a line through two points - positive gradient Ready to use Angharad Thomas 29/11/2018 21:35
Luis's copy of Find the equation of a line through two points - zero gradient draft Luis Hernandez 29/11/2018 21:07
Simon's copy of Equation of a line through two points - positive gradient draft Simon Thomas 20/05/2019 12:26
Maria's copy of Simon's copy of Equation of a line through two points - positive gradient draft Maria Aneiros 25/05/2019 07:25
Maria's copy of Find the equation of a line through two points - negative gradient draft Maria Aneiros 29/05/2019 05:07
Heather's copy of Find the equation of a line through two points - positive gradient draft Heather Driscoll 03/06/2019 14:27
Equation of a line through two points - positive gradient draft Heather Driscoll 03/06/2019 14:35
Equation of a line through two points draft Philip Charlton 17/06/2019 08:46
Find the equation of a line through two points - zero gradient draft Xiaodan Leng 10/07/2019 21:34
Equation of a line through two points - positive gradient draft Xiaodan Leng 10/07/2019 22:56
Adelle's copy of Straight line equation application: measuring sunflower height draft Adelle Colbourn 26/08/2019 04:27
Paul's copy of Straight line equation application: measuring sunflower height draft Paul Verheyen 06/09/2019 07:29
WordProblem02 draft Paul Verheyen 01/09/2019 15:35
Hoogtemeting van zonnebloemen draft Paul Verheyen 05/09/2019 20:29
Hoogte van zonnebloemen Ready to use Paul Verheyen 13/10/2019 15:39
Straight line equation application: measuring sunflower height draft steve kilgallon 27/10/2019 15:43
Voor Dirk draft Faye Caluwé 15/11/2019 21:46
Blathnaid's copy of Linear Equations - Find the equation of a line through two points draft Blathnaid Sheridan 07/11/2019 15:25

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: