Log equation 2

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Martin Jones

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Ready to use

3 years, 4 months ago

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Martin Jones 3 years, 4 months ago

Gave some feedback: Ready to use

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Martin Jones 3 years, 4 months ago

Published this.

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Martin Jones 3 years, 4 months ago

Created this as a copy of Log equation 1.

Name	Status	Author	Last Modified
Log equation 1	Ready to use	Martin Jones	09/02/2023 11:09
Log equation 2	Ready to use	Martin Jones	09/02/2023 11:10

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Question statement

Solve the equation

$\simplify{{B}*log(({A}-x)^2)}=\var{D}$

Give any introductory information the student needs.

			Name	Type	Generated Value

C	integer	5
D	number	10.5
B	integer	15
A	integer	54
x	decimal	dec("5.176127886143166038804504914753425766629e+1")
x2	decimal	dec("5.623872113856833961195495085246574233371e+1")

Automatically regenerate variables?

Name

Data type

Value

xxxxxxxxxx
 
random(2..10)

JME function reference

Description

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

Can an exam override the value of this variable?

Generated value: `integer`

This variable doesn't seem to be used anywhere.

Parts

Gap-fill
1. Gap Gap 0. Number entry
  Add
2. Gap Gap 1. Number entry
  Add

Gap-fill

Ask the student a question, and give any hints about how they should answer this part.

$x=\;$ Gap 0. or $x=\;$ Gap 1.

Advice

Starting from the equation

$\simplify{{B}*log(({A}-x)^2)}=\var{D}$

Divide by $\var{B}$ :

$\simplify{log(({A}-x)^2)}=\frac{\var{D}}{\var{B}}=\var{D/B}$

Take $10$ to the power:

$\simplify{({A}-x)^2}=10^\var{D/B}=\var{10^(D/B)}$

Square root:

$\simplify{{A}-x}=\pm\sqrt{\var{10^(D/B)}}=\pm\var{sqrt(10^(D/B))}$

Subtract from $\var{A}$ :

$x=\var{A}\mp\var{sqrt(10^(D/B))}=\var{x}\text{ or }\var{x2}$

Rounding to 2 decimal places gives $x=\var{precround(x,2)}$ or $x=\var{precround(x2,2)}$

Give a worked solution to the whole question.

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Part	Test	Passed?
Gap-fill
Gap-fill		Hasn't run yet
Number entry
Number entry		Hasn't run yet
Number entry
Number entry		Hasn't run yet

This question is used in the following exams:

Tess's copy of Equations involving logs by Tess Lynn in Tess's workspace.
Equations involving logs by Tess Lynn in Glasgow Numbas Question Pool.
Outcome 2 revision questions by Martin Jones in Martin's workspace.
Equations involving logs by Martin Jones in Martin's workspace.
Solve equations (incl logs) by Martin Jones in Martin's workspace.

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Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

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Checkpoint description

Martin Jones 3 years, 4 months ago

Martin Jones 3 years, 4 months ago

Martin Jones 3 years, 4 months ago

Error in variable testing condition

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Warning

Generated value: `integer`

Parts

Gap-fill

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Log equation 2

Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

Contributors

Feedback

History

Comment

Checkpoint description

Martin Jones 3 years, 4 months ago

Martin Jones 3 years, 4 months ago

Martin Jones 3 years, 4 months ago

Error in variable testing condition

Error

Warning

Generated value: integer

Parts

Gap-fill

Generated value: `integer`