// Numbas version: finer_feedback_settings {"name": "Asymptotes and intercepts", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"tags": [], "preamble": {"css": "", "js": ""}, "functions": {}, "variables": {"b": {"description": "", "group": "Ungrouped variables", "name": "b", "definition": "random(-12..12 except [0, a])", "templateType": "anything"}, "a": {"description": "", "group": "Ungrouped variables", "name": "a", "definition": "random(-12..12 except 0)", "templateType": "anything"}, "k": {"description": "", "group": "Ungrouped variables", "name": "k", "definition": "random(-12..12 except 0)", "templateType": "anything"}}, "name": "Asymptotes and intercepts", "advice": "
The vertical asymptote corresponds to the value of $x$ that results in attempting to divide by $0$. For the equation
\n\\[\\simplify[all]{y={k}/(x-{a})+{b}}\\]
\nThis means the equation of the vertical asymptote is $x=\\var{a}$.
\nThe horizontal asymptote corresponds to the value of $y$ that results from $x$ approaching infinity. As $x$ gets really really large, the fraction $\\simplify{{k}/(x-{a})}$ gets really really close to zero. The bigger $x$ gets, the closer $\\simplify{{k}/(x-{a})}$ gets to zero, and the closer $\\simplify[all]{y={k}/(x-{a})+{b}}$ gets to $y=\\var{b}$.
\nThis means the equation of the horizontal asymptote is $y=\\var{b}$.
\nNotice that in our equation, $\\var{k}$ is multiplying the fraction $\\simplify[all]{1/(x-{a})}$. It is a general fact that because $\\var{k}$ is positive the graph will be in the top right and bottom left parts of the plane. negative the graph will be in the top left and bottom right parts of the plane. We can see this as follows:
\nTo find the $y$-intercept, let $x=0$ and solve for $y$:
\n$y$ | \n$=$ | \n$\\simplify{{k}/(0-{a})+{b}}$ | \n
\n | $=$ | \n$\\simplify[fractionNumbers]{{-k/a+b}}$ | \n
To find the $x$-intercept, let $y=0$ and solve for $x$:
\n$0$ | \n$=$ | \n$\\simplify{{k}/(x-{a})+{b}}$ | \n
$\\var{-b}$ | \n$=$ | \n$\\simplify{{k}/(x-{a})}$ | \n
$\\simplify{{-b}(x-{a})}$ | \n$=$ | \n$\\var{k}$ | \n
$\\simplify{x-{a}}$ | \n$=$ | \n$\\simplify{{k}/({-b})}$ | \n
$x$ | \n$=$ | \n$\\simplify[fractionNumbers]{{-k/b+a}}$ | \n
Identifying some of the basic properties (intercepts, asymptotes, quadrants) of a right hyperbola.
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", "extensions": [], "ungrouped_variables": ["k", "a", "b"], "parts": [{"scripts": {}, "gaps": [{"scripts": {}, "maxValue": "{a}", "showCorrectAnswer": true, "notationStyles": ["plain", "en", "si-en"], "allowFractions": false, "type": "numberentry", "minValue": "{a}", "marks": 1, "correctAnswerStyle": "plain", "showFeedbackIcon": true, "variableReplacements": [], "correctAnswerFraction": false, "variableReplacementStrategy": "originalfirst"}], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "prompt": "The graph of this equation has a vertical asymptote at $x=$ [[0]].
", "variableReplacements": [], "type": "gapfill", "marks": 0}, {"scripts": {}, "gaps": [{"scripts": {}, "maxValue": "{b}", "showCorrectAnswer": true, "notationStyles": ["plain", "en", "si-en"], "allowFractions": false, "type": "numberentry", "minValue": "{b}", "marks": 1, "correctAnswerStyle": "plain", "showFeedbackIcon": true, "variableReplacements": [], "correctAnswerFraction": false, "variableReplacementStrategy": "originalfirst"}], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "prompt": "The graph of this equation has a horizontal asymptote at $y=$ [[0]].
", "variableReplacements": [], "type": "gapfill", "marks": 0}, {"scripts": {}, "gaps": [{"scripts": {}, "maxValue": "{b-k/a}", "showCorrectAnswer": true, "notationStyles": ["plain", "en", "si-en"], "allowFractions": true, "type": "numberentry", "minValue": "{b-k/a}", "marks": 1, "correctAnswerStyle": "plain", "showFeedbackIcon": true, "variableReplacements": [], "correctAnswerFraction": true, "variableReplacementStrategy": "originalfirst"}], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "prompt": "The $y$-intercept is at $y=$[[0]].
", "variableReplacements": [], "type": "gapfill", "marks": 0}, {"scripts": {}, "gaps": [{"scripts": {}, "maxValue": "{a-k/b}", "showCorrectAnswer": true, "notationStyles": ["plain", "en", "si-en"], "allowFractions": true, "type": "numberentry", "minValue": "{a-k/b}", "marks": 1, "correctAnswerStyle": "plain", "showFeedbackIcon": true, "variableReplacements": [], "correctAnswerFraction": true, "variableReplacementStrategy": "originalfirst"}], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacementStrategy": "originalfirst", "prompt": "The $x$-intercept is at $x=$ [[0]].
\n", "variableReplacements": [], "type": "gapfill", "marks": 0}], "type": "question", "contributors": [{"name": "Denis Flynn", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/1216/"}]}]}], "contributors": [{"name": "Denis Flynn", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/1216/"}]}