New FP3 Paper 5

1. Figure 1

Figure 1 shows a sketch of the curve with parametric equations

x = a cos3 t, y = a sin3 t, 0 £ t £ ,

where a is a positive constant.

The curve is rotated through 2p radians about the x-axis. Find the exact value of the area of the curved surface generated. (7)

2. a) Show that, for 0 < x £ 1,

ln = –ln . (3)

(b) Using the definition of cosh x or sech x in terms of exponentials, show that, for 0 < x £ 1,

arsech x = ln . (5)

(c) Solve the equation

3 tanh2 x – 4 sech x + 1 = 0,

giving exact answers in terms of natural logarithms. (5)

3. The line l1 has equation

r = i + 6j – k + l(2i + 3k)

and the line l2 has equation

r = 3i + pj + m(i – 2j + k), where p is a constant.

The plane contains l1 and l2.

(a) Find a vector which is normal to . (2)

(b) Show that an equation for is 6x + y – 4z = 16. (2)

(c) Find the value of p. (1)

The plane has equation r.(i + 2j + k) = 2.

(d) Find an equation for the line of intersection of and , giving your answer in the form

(r – a) ´ b = 0. (5)

4. A = .

(a) Show that det A = 20 – 4k. (2)

(b) Find A–1. (6)

Given that k = 3 and that is an eigenvector of A,

(c) find the corresponding eigenvalue. (2)

Given that the only other distinct eigenvalue of A is 8

(d) find a corresponding eigenvector. (4)

5. Evaluate dx, giving your answer as an exact logarithm (5)

6. Given that

In =

(a) show that In = In – 1 , n ³ 1. (6)

Given that ,

(b) use the result in part (a) to find the exact value of . (3)

7. The point S, which lies on the positive x-axis, is a focus of the ellipse with equation + y2 = 1.

Given that S is also the focus of a parabola P, with vertex at the origin, find

(a) a cartesian equation for P, (4)

(b) an equation for the directrix of P. (1)

8. (a) Using the definition of cosh x in terms of exponentials, prove that

4 cosh3 x – 3 cosh x = cosh 3x. (3)

(b) Hence, or otherwise, solve the equation

cosh 3x = 5 cosh x,

giving your answer as natural logarithms. (4)

The End