Edexcel C4 June 2011 exam answers review

9x²/(x – 1)²(2x + 1) = A/(x – 1) + B/(x – 1)² + C/(2x + 1)

Find the values of the constants A, B and C.

(4)

ANSWER
f(x) = 1/√(9 + 4x²)

Find the first three non-zero terms of the binomial expansion of f (x) in ascending powers of x. Give each coefficient as a simplified fraction.

(6)

ANSWER

A hollow hemispherical bowl is shown in Figure 1. Water is flowing into the bowl. When the depth of the water is h m, the volume V m3 is given by

V = ½πh²(3− 4h), 0≤h≤0.25
  1. Find, in terms of π, dV/dh when h = 0.1(6)
  2. Water flows into the bowl at a rate of π/800m³s-1

  3. Find the rate of change of h, in m s–1, when h = 0.1(6)
ANSWER
[IMAGE]

Figure 2 shows a sketch of the curve with equation y = x³ ln (x2 + 2), x≥0. The finite region R, shown shaded in Figure 2, is bounded by the curve, the x-axis and the line x =√2.

The table below shows corresponding values of x and y for y = x³ln (x² + 2).

x 0 √2/4 √2/2 3√2/4 √2
y 0 0.3240 3.9210
  1. Complete the table above giving the missing values of y to 4 decimal places.
  2. Use the trapezium rule, with all the values of y in the completed table, to obtain an estimate for the area of R, giving your answer to 2 decimal places.(2)
  3. Use the substitution u = x² + 2 to show that the area of R is
    ½\( \int_{4}^{2} \)(u – 2)lnu du

    (3)

  4. Hence, or otherwise, find the exact area of R. (6)
ANSWER
Find the gradient of the curve with equation

ln y = 2x ln x, x>0, y>0

at the point on the curve where x = 2. Give your answer as an exact value. (7)

ANSWER

With respect to a fixed origin O, the lines l1 and l2 are given by the equations

[IMAGE]

where λ and µ are scalar parameters.

  1. Show that l1 and l2 meet and find the position vector of their point of intersection A.(6)
  2. Find, to the nearest 0.1°, the acute angle between l1 and l1.(3)
  3. The point B has position vector [IMAGE]

  4. Show that B lies on l1(1)
  5. Find the shortest distance from B to the line 2 l , giving your answer to 3 significant figures.(4)
ANSWER
[IMAGE]
Figure 3 shows part of the curve C with parametric equations

x = tanθ, y = sinθ, 0≤θ<π/2

The point P lies on C and has coordinates (√2, ½√3)

  1. Find the value of θ at the point P.(2)
  2. The line l is a normal to C at P. The normal cuts the x-axis at the point Q.

  3. how that Q has coordinates (k√3, 0), giving the value of the constant k.(6)
  4. The finite shaded region S shown in Figure 3 is bounded by the curve C, the line x = √3 and the x-axis. This shaded region is rotated through 2π radians about the x-axis to form a solid of revolution.

  5. Find the volume of the solid of revolution, giving your answer in the form pπ√3 + qπ², where p and q are constants.(7)
ANSWER
  1. Find \( \int \)(4y+3)½dy(2)
  2. Given that y =1.5 at x = – 2, solve the differential equation
    dy/dx = √(4y+3)/x²

    giving your answer in the form y = f (x).(6)

ANSWER

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