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2.13 Further rational functionsIB Maths: Analysis and Approaches HL: Subtopic test

10 questions, 27 marks

IB Maths: Analysis and Approaches HL

2.13 Further rational functions

Total 27 marks

Name

Class

Date

  1. 1
    The function ff is defined by f(x)=2x+3x2−x−6f(x) = \dfrac{2x + 3}{x^{2} - x - 6}, for x∈Rx \in \mathbb{R}, x≠−2x \ne -2, x≠3x \ne 3.
    (a)
    Write down the equations of the vertical asymptotes of the graph of y=f(x)y = f(x).
    [1 mark]
    • Ax=−3x = -3 and x=2x = 2
    • Bx=3x = 3 and x=−2x = -2
    • Cx=−32x = -\frac{3}{2}
    • Dy=3y = 3 and y=−2y = -2
    (b)
    Write down the equation of the horizontal asymptote of the graph of y=f(x)y = f(x).
    [1 mark]
    • Ay=0y = 0
    • By=2y = 2
    • Cy=−12y = -\frac{1}{2}
    • Dy=2xy = 2x
    (c)
    Find the coordinates of the points where the graph of y=f(x)y = f(x) meets the axes.
    [2 marks]

    Total for question 1: 4 marks

  2. 2
    The function gg is defined by g(x)=x2+3x−1x−2g(x) = \dfrac{x^{2} + 3x - 1}{x - 2}, for x∈Rx \in \mathbb{R}, x≠2x \ne 2.
    (a)
    Find the equation of the oblique asymptote of the graph of y=g(x)y = g(x).
    [1 mark]
    • Ay=x+3y = x + 3
    • By=x+1y = x + 1
    • Cy=x+5y = x + 5
    • Dy=x−5y = x - 5
    (b)
    Find the coordinates of the yy-intercept of the graph of y=g(x)y = g(x).
    [1 mark]
    • A(0,−12)\left(0, -\frac{1}{2}\right)
    • B(0,−1)(0, -1)
    • C(0,−92)\left(0, -\frac{9}{2}\right)
    • D(0,12)\left(0, \frac{1}{2}\right)
    (c)
    Find the exact xx-coordinates of the points where the graph of y=g(x)y = g(x) meets the xx-axis.
    [2 marks]

    Total for question 2: 4 marks

  3. 3
    The function hh is defined by h(x)=ax+bx2+cx−8h(x) = \dfrac{ax + b}{x^{2} + cx - 8}, where a,b,c∈Ra, b, c \in \mathbb{R}. The graph of y=h(x)y = h(x) has vertical asymptotes x=2x = 2 and x=−4x = -4, an xx-intercept at (−2,0)(-2, 0) and a yy-intercept at (0,−12)\left(0, -\frac{1}{2}\right).
    (a)
    Find the values of aa, bb and cc.
    [3 marks]
    (b)
    Show that the equation h(x)=kh(x) = k has at least one real solution for every k∈Rk \in \mathbb{R}. State what this tells you about the range of hh.
    [4 marks]

    Total for question 3: 7 marks

  4. 4
    A courier company models the mean cost per parcel, CC dollars, when a van delivers xx hundred parcels in a day by C(x)=x2+4x+68x+2C(x) = \dfrac{x^{2} + 4x + 68}{x + 2}, for x>0x > 0.
    (a)
    (i) Show that C(x)=x+2+64x+2C(x) = x + 2 + \dfrac{64}{x + 2}.
    (ii) Write down the equations of the asymptotes of the graph of
    y=x2+4x+68x+2y = \dfrac{x^{2} + 4x + 68}{x + 2}, x∈Rx \in \mathbb{R}, x≠−2x \ne -2.
    (iii) Explain why this graph does not meet the
    xx-axis.
    (iv) Interpret the oblique asymptote in the context of the model.
    [6 marks]
    (b)
    Find the number of parcels that minimises the mean cost per parcel, and the minimum mean cost. The company regards a day as efficient if the mean cost per parcel is at most 20 dollars. Find the range of the number of parcels delivered on an efficient day.
    [6 marks]

    Total for question 4: 12 marks

End of questions