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This question tests the student's understanding of what is and is not a surd, and on their simplification of surds.
\nTranslated to German, minor changes to advice section.
\nOriginal: https://numbas.mathcentre.ac.uk/question/22497/surds-simplification/ by Lauren Richards.
", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "Einige einfache Aufgaben zur Vereinfachung von Ausdrücken mit Quadratzahlen.
", "advice": "$\\sqrt{\\var{square}}$ und $\\sqrt[3]{\\var{cube}}$ sind rational, und zwar sogar ganze Zahlen: $\\simplify{{sqrt(square)}}$ bzw. $\\var{root}$.
\n$\\sqrt{\\var{h}}$, $\\sqrt{\\var{j}}$ und $\\sqrt{\\var{k}}$ sind irrational. Es gibt keine ganzen Zahlen $a, b$, $b\\ne 0$ so dass $\\left(\\frac ab\\right)^2=\\var{h}$ (oder $= \\var{j}$ oder $=\\var{k}$). Eine Möglichkeit, das zu sehen, ist, den Satz über die eindeutige Primzaktorzerlegung von ganzen Zahlen zu benutzen. Wenn $\\left(\\frac ab\\right)^2=\\var{h}$ gilt, also $a^2 = hb^2$, dann kommt in der eindeutigen Primfaktorzerlegung der linken Seite jede Primzahl mit einem geraden Exponenten vor; auf der rechten Seite ist das nicht der Fall.
\n\n\nBenutzen SIe, dass $\\sqrt{a}\\times\\sqrt{b}=\\sqrt{ab}$.
\nWir suchen nach einer Quadratzahl, die $ab$ teilt, und schreiben das als $\\sqrt{b^2}\\times\\sqrt{a}$.
\ni)
\n$\\sqrt{48}$ = $\\sqrt{16}\\times\\sqrt3$
\n$\\sqrt{16}$ ist $4$, also ist die Antwort: $4\\sqrt3$.
\nii)
\n$\\sqrt{56}$ = $\\sqrt{4}\\times\\sqrt{14}$
\n$\\sqrt4$ ist $2$, also erhalten wir: $2\\sqrt{14}$.
\niii)
\n$\\sqrt{32}$ = $\\sqrt{16}\\times\\sqrt{2}$
\n$\\sqrt{16}$ ist $4$, wir bekommen also: $4\\sqrt2$.
\niv)
\n$\\sqrt{44}$ = $\\sqrt{4}\\times\\sqrt{11}$
\n$\\sqrt4$ ist $2$, also erhalten wir: $2\\sqrt{11}$.
\n\nBeachten Sie, dass $\\sqrt{\\var{a}}$ und $\\sqrt{\\var{d}}$ Wurzeln aus Quadratzahlen sind.
\n$\\sqrt{\\var{a}}$ = $\\var{sqrta}$, folglich:
\ni) $\\sqrt{\\var{c}}$ = $\\sqrt{\\var{a}}$ x $\\sqrt{\\var{b}}$ = $\\var{sqrta}\\sqrt{\\var{b}}$ and
\nii) $\\sqrt{\\var{g}}$ = $\\sqrt{\\var{d}}$ x $\\sqrt{\\var{f}}$ = $\\var{sqrtd}\\sqrt{\\var{f}}$.
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\n", "minMarks": 0, "maxMarks": 0, "minAnswers": 0, "maxAnswers": 0, "shuffleChoices": false, "shuffleAnswers": false, "displayType": "radiogroup", "warningType": "none", "showCellAnswerState": true, "choices": ["$\\sqrt{\\var{square}}$
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\n[[0]]
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\n$\\displaystyle\\sqrt{\\var{c}}$ = [[0]]$\\displaystyle\\sqrt{\\var{b}}$
\n$\\displaystyle\\sqrt{\\var{g}}$ = [[1]]$\\displaystyle\\sqrt{\\var{f}}$
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