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Domain and Range — Free MYP5 Mathematics (Extended) Practice Questions
1QuestionRestrictionsConcept Practice
4 marks~6 minCriterion A
A chemical plant monitors the concentration of a coolant in a pipe. The concentration (in grams per litre) at time x hours after startup is modelled by
f(x)=x−34+2,x>0.
The function has a vertical asymptote at x=3 and a horizontal asymptote at y=2.
a
Explain how each asymptote restricts the domain and range of f. [2]
b
Calculate f(5). [1]
c
The pipe is safe to operate only when the concentration exceeds 3 g/L. Justify whether the pipe is safe to operate at x=5 hours. [1]
Solutions
2QuestionRange from graphsAssessment Practice
3 marks~5 minCriterion D
A drone delivery company models the height of a package above ground during a short flight using the function h(t)=t2−4t+3, where h is the height in metres and t is the time in seconds. The graph of h(t) shows a parabola with vertex (2,−1) that opens upwards.
a
Deduce the range of h(t). [1]
b
The package must remain at or above ground level (h≥0) throughout the flight. Justify whether this model is physically valid, using your answer to part (a). [2]
Solutions
3QuestionRange from graphsAssessment Practice
4 marks~6 minCriterion B
A structural engineer models the vertical clearance beneath four cable-stay bridge sections using quadratic functions. Each function gives height y (metres) at horizontal position x (metres), with the vertex representing the lowest or highest point of the cable profile.
The four cable profiles are:
f(x)=x2, vertex (0,0), opens upward
g(x)=x2+3, vertex (0,3), opens upward
h(x)=(x−2)2, vertex (2,0), opens upward
k(x)=−(x+1)2+4, vertex (−1,4), opens downward
a
State the range of each function. [1]
b
Analyse the relationship between the vertex y-coordinate, the direction of opening, and the range of each profile. Deduce a general rule connecting the sign of a and the vertex y-coordinate k to the range of a(x−h)2+k. [2]
c
A new bridge section requires a cable profile m(x)=a(x−h)2+k whose height never exceeds −3 m relative to the reference datum, so the range must be (−∞,−3]. Construct a valid function m(x) satisfying this condition, and justify whether a cable profile with range (−∞,−3] is physically safe for vehicles passing beneath the bridge. [1]
Solutions
4QuestionRange from graphsAssessment Practice
5 marks~8 minCriterion C
A hospital monitoring system records a patient's oxygen saturation level, f(x) (%), over a 24-hour period. The piecewise function f(x) is represented by the graph below.
The graph consists of three parts: - a horizontal segment at y=4 for −5≤x<−2, with a closed circle at (−5,4) and an open circle at (−2,4) - a downward-opening parabola with vertex (0,3), passing through (−2,1) and (2,1), with closed circles at both endpoints - a curve for x>2 starting at (2,1) with a closed circle, decreasing toward the asymptote y=−1 as x→∞, never reaching y=−1
a
State the y-value produced by the horizontal segment and identify whether it is included in the range. [1]
b
Deduce the set of y-values contributed by the parabola and by the asymptotic curve, showing your reasoning for each endpoint. [2]
c
Interpret the complete range of f(x) in interval notation, and justify whether the gap in the range gives cause for clinical concern about the reliability of the monitoring data. [2]