The Vietnamese Mathematical Hobby Group

MATHEMATICAL TEST PAPER #20

 

Question 1:

(a) Evaluate (i) (ii) using the subst. u = 1 + 5x.

(b) The polynomial has a factor (x + 3). Find the value of a.

(c) The point P(-3, 8) divides the interval AB externally in the ratio k:1 . If A is the point (6,-4), find the value of k.

(d) (i) Sketch the graph of y = |x - 2|

(ii) For what values of x is |x - 2| < x ?

 

Question 2:

(a) Consider wher k is a constant.

(i) Find and

(ii) Determine the values of k for which satisfies the equation

(b) When Mendel crosses a tall strain of pea with a dwarf strain of pea, he found that 3/4 of the offspring were tall and 1/4 were dwarf.

Suppose that five such offspring were selected at random. Find the probability that

(i) all of these offspring were tall;

(ii) at least three of these offspring were tall.

(c) The diagram shows two circles intersecting at A and B. The diameter of one circle is AC. Copy this diagram into your booklet.

(i) On your diagram draw a straightline through A, parallel to CB, to meet the second circle in D.

(ii) Prove that BD is a diameter of the second circle

(iii) Suppose that BD is parallel to CA. Prove that the circles have equal radii.

 

Question 3:

 

(a) Taking x=0.5 as a first approximation to the root of the equation , use Newton's method to find a second approximation.

(b) Evaluate

(c) If , find dy/dx when x = 1.

(d) The volume V of a sphere of radius r mm is increasing at a constant rate of 200 mm3 per second

(i) Find in terms of r.

(ii) Determine the rate of increase of the surface area S of the sphere when the radius is 50 mm (note: )

 

Question 4:

 

(a) Use mathematical induction to prove that, for all positive integers n,

1 + 2 + 4 + . . . . . +

(b) The acceleration of a particle moving in a straight line is given by , where x is the displacement in metres from the origin O and t is the time in seconds. Initially, the particle is at rest at x=4.

(i) If the velocity of the particle is v m/s show that .

(ii) Show that the particle does not pass through the origin.

(iii) Determine the position of the particle when v=10.

 

(c) Containers are coded by different arrangements of coloured dots in a row, the colour are white and at most one is blue.

(i) Find the number of different codes possible if six dots are used.

(ii) On some containers only 5 dots are used. Find the number of different codes possible in this case.

 

Question 5:

(a) Consider the function

(i) Evaluate f(2)

(ii) Draw a graph of y = f(x)

(iii) State the domain and range of y = f(x).

(b) (i) Sketch the parabola whose parametric equations are x = t and y = t2. On your diagram mark the points P and Q which correspond to t = -1 and t=2, respectively.

(ii) Show that the tangents to the parabola at P and Q intersect at R(1/2, -2).

(iii) Let T(t, t2) be the point on the parabola between P and Q such that the tangent at T meets QR at the midpoint of QR. Show that the tangent at T is parallel to PQ.

 

Question 6:

 

(a) (i) On the same axes, sketch the curve y = sin x , y= cos x, and y = sinx + cos x, for 0<x<2p.

(ii) From your graph, determine the number of values of x in the interval 0<x<2p for which sinx + cosx = 1.

(iii) For what values of the constant k does sinx + cosx = k have exactly two solutions in the interval 0<x<2p.

 

(b) The following diagram shows the path of a projectile launched at an angle of elevation a, with an initial velocity 40 m/s, from the top of a 50 m high building. The acceleration due to gravity is assumed to be 10 m/s2.

(i) Given that , show that the x- and y- component of displacement are

(ii) The projectile lands on the ground 200 m from the base of the building. Find the two possible values for a.

 

 

Question 7:

(a) Let

(i) for what values of x is f(x) undefined.

(ii) Show that y = f(x) is an odd function

(iii) Show that f'(x)<0 at all values x for which the function is defined.

(iv) Hence sketch the graph y = f(x).

(b) In the diagram a vertical pole AB, 3 m high, is placed on top of a support 1 m high. The pole subtends an angle of q radians at the point P, which is x m from the base 0 of the support.

(i) Show that

(ii) Show that q is maximum when x=2.

(iii) Deduce that the maximum angle subtended at P is .