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"pickQuestions": 0}], "name": "The distance between two complex numbers", "showQuestionGroupNames": false, "functions": {}, "parts": [{"showCorrectAnswer": true, "scripts": {}, "gaps": [{"correctAnswerFraction": false, "showCorrectAnswer": true, "scripts": {}, "allowFractions": false, "type": "numberentry", "maxValue": "ans1+tol", "minValue": "ans1-tol", "variableReplacementStrategy": "originalfirst", "variableReplacements": [], "marks": 1, "showPrecisionHint": false}], "type": "gapfill", "variableReplacementStrategy": "originalfirst", "prompt": "\n \n \n

Find the distance between $\\var{z1}$ and $\\var{z2}$.

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Distance = [[0]]

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Find the distance between $\\var{z3}$ and $\\var{z4}$.

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Distance = [[0]]

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Find the distance between $\\var{z5}$ and $\\var{z6}$.

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Distance = [[0]]

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Find the distance between the following complex numbers, leaving your answer in decimal form to 3 decimal places:

", "tags": ["checked2015", "complex numbers", "distance between complex numbers", "mas1602", "MAS1602", "modulus", "modulus of a complex number", "modulus of complex numbers"], "rulesets": {"std": ["all", "!collectNumbers", "fractionNumbers", "!noLeadingMinus"]}, "preamble": {"css": "", "js": ""}, "type": "question", "metadata": {"notes": "

15/07/2015:

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Added tags.

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5/07/2012:

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Added tags.

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Perhaps more steps are needed in the solutions? It isn't explained how to find the modulus of the complex number. Explanation included in Advice.

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Question appears to be working correctly.

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13/07/2012:

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Set new variable tol=0 for all numeric input.

", "licence": "Creative Commons Attribution 4.0 International", "description": "

Finding the distance between two complex numbers using the modulus of their difference. Three parts.

"}, "advice": "\n \n \n

The distance D between two complex numbers $z_1=a+bi$ and $z_2=c+di$ is given by the modulus of the difference i.e.
\\[D=|z_1-z_2| = |(a-c)+(b-d)i|=\\sqrt{(a-c)^2+(b-d)^2}\\]
Applying to the questions we have:\t\t\t\t\t
a) \\[ \\begin{eqnarray*} D&=&|(\\var{z1})-(\\var{z2})|\\\\\n \n &=&|\\var{z1-z2}|\\\\\n \n &=& \\var{abs(z1-z2)}\\\\\n \n &=&\\var{ans1}\n \n \\end{eqnarray*} \\] to 3 decimal places.

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b) \\[ \\begin{eqnarray*} D&=&|(\\var{z3})-(\\var{z4})|\\\\\n \n &=&|\\var{z3-z4}|\\\\\n \n &=& \\var{abs(z3-z4)}\\\\\n \n &=&\\var{ans2}\n \n \\end{eqnarray*} \\] to 3 decimal places.

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c) \\[ \\begin{eqnarray*} D&=&|(\\var{z5})-(\\var{z6})|\\\\\n \n &=&|\\var{z5-z6}|\\\\\n \n &=& \\var{abs(z5-z6)}\\\\\n \n &=&\\var{ans3}\n \n \\end{eqnarray*} \\] to 3 decimal places.

\n \n \n ", "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}]}]}], "contributors": [{"name": "Newcastle University Mathematics and Statistics", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/697/"}]}