AAHL Sample Paper 3 Agnesi
AAHL Sample Paper 3 Agnesi
AAHL Sample Paper 3 Agnesi
Answer all questions in the answer booklet provided. Please start each question on a new page. Full
marks are not necessarily awarded for a correct answer with no working. Answers must be supported
by working and/or explanations. Solutions found from a graphic display calculator should be supported
by suitable working. For example, if graphs are used to find a solution, you should sketch these as part
of your answer. Where an answer is incorrect, some marks may be given for a correct method, provided
this is shown by written working. You are therefore advised to show all working.
This question asks you to explore the derivation and properties of a curve known
as the “witch of Agnesi.”
N
the same y-coordinate as point A. Both points A and C lie on a line passing
IO
through the origin at an angle of inclination θ, where 0 < θ < π.
AT
AM LE
IN
P
EX M
K A
S
C
O
x
(a) (i) Show that cos θ = . [2]
x 2 + 4a 2
M
(ii) Show that the equation of the line passing through OC is y = x tan θ. [2]
(iii) Using the result of part (ii), show that x = 2a cot θ. [2]
(Question 1 continued)
(b) By eliminating θ, show that the equation of the path of point P is given by:
8a 3
y= [5]
x 2 + 4a 2
8a 3
(c) Show that y = is an even function. [1]
x 2 + 4a 2
(d) Find the coordinates of the points of inflexion. Give your answer in terms of a. [7]
N
8a 3
(e) Sketch the graph of y= , labelling the stationary point, points of
x 2 + 4a 2
IO
inflexion and any asymptotes. [3]
AT
AM LE
∞ R
∫k R→∞ ∫k
You may use the fact that f (x) d x = lim f (x) d x without proof.
IN
P
EX M
8a 3
(f) (i) Find the area under the curve y = for x ∈ ℝ. [5]
x 2 + 4a 2
K A
S
(ii) Describe the effect on the area under the curve if the value of a is doubled.
Justify your answer with an appropriate calculation. [2]
C
O
M
Turn over