Maria's copy of De Moivre's theorem - Square Root

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Maria Aneiros 5 years, 10 months ago

Created this as a copy of De Moivre's theorem - Square Root.

Name	Status	Author	Last Modified
DeMoivre's theorem 1	Ready to use	Frank Doheny	04/04/2017 08:31
De Moivre's theorem 2	Ready to use	Frank Doheny	04/04/2017 08:33
De Moivre's theorem 3	Ready to use	Frank Doheny	04/04/2017 08:42
DeMoivre's Theorem 1	draft	Peter Johnston	07/04/2017 07:29
De Moivre's theorem - Square Root	draft	Peter Johnston	07/04/2017 07:27
Maria's copy of DeMoivre's Theorem 1	draft	Maria Aneiros	25/05/2019 08:24
Maria's copy of De Moivre's theorem - Square Root	draft	Maria Aneiros	11/06/2019 06:19

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Question statement

Use De Moivre's theorem to find a square root of $Z=\var{x}+\var{y}i$

Give any introductory information the student needs.

			Name	Type	Generated Value

x	integer	4
y	integer	3
n	number	0.5
theta	decimal	dec("6.435011087932843868028092287173226380415e-1")
mod	number	5
x2	number	2.1213203436
y2	number	0.7071067812

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Name

Data type

Value

A random number between and (inclusive) with step size

Description

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

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Generated value: `integer`

→ Used by:

mod
theta

Parts

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

$\sqrt{\var{x}+\var{y}i}=\pm(A+Bi)$

Calculate $A$ and $B$

$A$ = Gap 0.

$B$ = Gap 1.

Advice

To evaluate $\sqrt{\var{x}+\var{y}i}$ we must first express $Z=\var{x}+\var{y}i$ in polar form.

The modulus of $\var{x}+\var{y}i$ = $\sqrt{\var{x}^2+(\var{y})^2}=\sqrt{\simplify{{x^2}+{y}^2}}$

The argument of the complex number is given by $\theta=\tan^{-1}\left(\frac{\var{y}}{\var{x}}\right)=\var{theta}$

According to De Moivre's theorem $Z^{\var{n}}=|Z|^{\var{n}}\left(\cos(\var{n}*\theta)+i\sin(\var{n}*\theta)\right)$

$(\simplify{{x}+{y}i})^\var{n}=\left(\sqrt{\simplify{{x^2}+{y}^2}}\right)^{\var{n}}\left(\cos(\simplify{{n}*{theta}})+i\sin(\simplify{{n}*{theta}})\right)$

= $\simplify{{x2}+{y2}i}$

$A=\var{x2}$ and $B=\var{y2}$

Give a worked solution to the whole question.

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Part	Test	Passed?
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Number entry
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This question is used in the following exam:

Maths 1A - Homework Week 9 (Complex Numbers) by Maria Aneiros in MY QUESTIONS.

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Maria's copy of De Moivre's theorem - Square Root

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Taxonomy: mathcentre

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Taxonomy: Context

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Checkpoint description

Maria Aneiros 5 years, 10 months ago

Error in variable testing condition

Error

Warning

Generated value: `integer`

Parts

Gap-fill

Loading...

Error

Maria's copy of De Moivre's theorem - Square Root

Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

Contributors

History

Comment

Checkpoint description

Maria Aneiros 5 years, 10 months ago

Error in variable testing condition

Error

Warning

Generated value: integer

Parts

Gap-fill

Generated value: `integer`