A-level · Algebra & functions

Sketching curvesExam-style questions

Drawing a curve from its equation without plotting points. Where it meets the axes, read from the factors; which way the ends go, from the leading term; whether it crosses or touches at each root; reciprocal curves and their asymptotes; finding where two curves meet; and counting meeting points from a sketch or with the discriminant.

17 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4Level 5
  1. 1
    It is given that

    f(x)=x(x+4)(b−x)\mathrm{f}(x) = x(x + 4)(b - x)

    where bb is a positive constant.

    Sketch the graph of y=f(x)y = \mathrm{f}(x)

    (3 marks)
    Level 2 · 3 marksTry it
  2. 2
    The line y=5−xy = 5 - x meets the curve y=6xy = \dfrac{6}{x}. Find the coordinates of the points of intersection.
    Level 3 · 3 marksTry it
  3. 3
    O(1, −7)(5, 25)xyFigure 1

    The curve CC, shown in Figure 1, has equation y=g(x)y = \text{g}(x), where g\text{g} is a cubic function.

    The curve passes through the origin OO, and its turning points are at (1, −7)(1,\ -7) and (5, 25)(5,\ 25).
    (a) Write down the set of values of xx for which g′(x)<0\text{g}'(x) < 0

    (1 mark)

    The line with equation y=ky = k, where kk is a constant, has exactly one point of intersection with CC.
    (b) Find the set of values of kk, giving your answer in set notation.

    (2 marks)
    Level 3 · 3 marksTry it
  4. 4
    The curve C1C_1 has equation

    y=3x2+2x>0y = 3x^2 + 2 \qquad x > 0

    The curve C2C_2 has equation

    y=36x−4x>0y = \frac{36}{x} - 4 \qquad x > 0
    (a) Verify that the curves intersect at x=2x = 2

    (2 marks)
    (b) Write down the yy coordinate of the point of intersection.

    (1 mark)
    Level 3 · 3 marksTry it
  5. 5
    O(−2, 14)(4, −40)xyFigure 1

    Figure 1 shows a sketch of the curve CC with equation y=f(x)y = \text{f}(x), where f(x)\text{f}(x) is a polynomial of degree 3.

    The curve passes through the origin OO and has stationary points at (−2, 14)(-2,\ 14) and (4, −40)(4,\ -40).
    (a) Write down the set of values of xx for which f′(x)<0\text{f}'(x) < 0

    (1 mark)

    The line ll has equation y=ky = k, where kk is a constant.

    Given that ll meets CC at exactly one point,
    (b) find the set of values of kk, giving your answer in set notation.

    (2 marks)
    Level 3 · 3 marksTry it

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