MATH1131 MATHEMATICS 1A Semester 2 2016
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Semester 2 2016
MATH1131
MATHEMATICS 1A
1. i) Determine the value of each of the following limits or explain why the limit does not exist.
3x2 + 4
x→r 6x2 - 8x + 3
2
|x - 3|
x→3 x - 3
d) x(l) ╱ 1 + 、x
ii) Evaluate the following integrals:
a) I1 = ń1 e x3 ln x dx,
b) I2 = ń0 4 cos x sin4 x dx.
iii) Consider the equation ln(1 + x) = cos x.
a) Show that this equation has at least one positive solution.
b) Can the equation have any solution for x > 2? Give reasons for your answer.
iv) Find all values of a and b (if any) such that the function g : 妓 → 妓 given by
g(x) =
is both continuous and differentiable at 0.
v) Given that y = (1 - 3x)cos x, find dy
2. i) Let f : 妓 → 妓 be defined by f (x) = 1 + sinh x coshx.
a) Using the definitions of sinh x and cosh x show that sinh 2x = 2 sinh x coshx.
b) State the range of f .
c) Explain why f has an inverse function g : 妓 → 妓.
d) Find the value of go (1).
ii) Determine, with reasons, whether or not the following improper integral
converges.
ń1 r dx
iii) a) State carefully the Mean Value Theorem.
b) Illustrate the Mean Value Theorem for the function f (x) = x2 on the interval [-a, a + 4] where a > 0.
c) By applying the Mean Value Theore on the interval [0, π/2] prove that the function
g(x) = x2 cos(5x) - (x - )2 sin(7x)
has a stationary point.
iv) Suppose that f : 妓 → 妓 is a continuous function on 妓. Let
g(x) = ń0 x f (u)(x - u) du and h(x) = ń0 x ╱ń0 u f (t) dt、 du.
a) Show that go (x) = ho (x).
b) What are the values of g(0) and h(0)?
c) Prove that g(x) = h(x) for all x e 妓.
3. i) Let z = 4 + i and w = 2 - 2i.
a) Find zw in Cartesian form.
b) Find w/z in Cartesian form.
c) Find |w15 |.
d) Find Arg(4w).
ii) Consider the line e given by
x = )(│) 2(3) + t )(│)-1 for t e 妓,
and the plane p with Cartesian equation 3x + 2y + z = 15. Find the point of intersection of the line e and the plane p .
iii) The points A, B and C in 妓3 have position vectors
a = )(│) , b = )(│) 2-41 and c = )(│) .
_→ _→
a) Write down the vectors AB and AC .
b) Hence or otherwise, find the position vector of the point D such that ABCD (in that order) is a parallelogram.
c) Find a vector equation of the line which passes through C and is _→
parallel to AB .
d) Write down a parametric vector equation of the plane which passes through the points A, B and C .
e) Find the Cartesian equation of the plane in part (d).
iv) Let A be the matrix
A = │ 2(1) ) 3
-3
-2
-2
1(3) ←
1 {
and let I denote the 3 × 3 identity matrix.
Use the following Maple session to assist you in answering the questions below.
> with(LinearAlgebra):
> A := <<1,2,3>|<-3,-2,-2>|<3,1,1>>;
- 1 A := 2 ' > A2 := A.A; - 4 A2 := 1 ' 2 > A3 := A.A2; - 7 A3 := 8 ' |
-3 -2 -2
-3 -4 -7
-12 -5 -8 |
3 ; 1 '
3 ; 5 8 ' 12 ; 4 ' |
a) Find A3 - 4A and express it as a scalar multiple of I .
b) Hence express A6 in terms of A2 , A and I .
c) Using part (a), or otherwise, find A_1 .
v) Sketch the following region on an Argand diagram:
S =)z e 仑 : - < Arg(z - 1 - i) < 」.
vi) Let u = )(│) and v = )(│) 30-1 be two vectors in 妓3 .
a) Prove that u and v are perpendicular.
b) State whether or not {u, v, u × v} is an orthonormal set.
4. i) Find the three cube roots of -8, expressing your answers in a + ib form.
ii) By solving an appropriate system of linear equations find a parametric vector equation of the line of intersection of the two planes with Cartesian equations x + y - 5z = 5 and x + 2y - 7z = 6.
iii) Let A = │ ←
) 3 2 1 {
a) Calculate the determinant of A.
b) Is the matrix A invertible? Give reasons.
iv) Let c be the line in 妓3 with a parametric vector equation )(│) = )(│) 3 + t )(│) , t e 妓,
and Q be a point in 妓3 with position vector O(-)Q(→) = │ 0(1) ←
) 1 {.
a) Write down a vector v parallel to c and a point P on c. -→
b) Using P and v from part (a), find the projection of PQ onto v .
c) Hence determine the point on the line c which is closest to Q.
v) During a holiday Misty caught a total of x flathead, y mullet and z garfish. To catch each flathead she needed to use 1 worm, walk 2 kilometres and fish for 1 hour. To catch each mullet she needed to use 4 worms, walk 9 kilometres and fish for 5 hours. To catch each garfish she needed to use
2 worms, walk 5 kilometres and fish for 5 hours. Altogether she used 25 worms, walked for 59 kilometres and fished for 46 hours.
a) Explain why x + 4y + 2z = 25.
b) Write down a system of linear equations that determine x, y and z .
c) Reduce the system in (b) to echelon form and solve to find the number of fish of each type caught.
vi) Suppose that A is a 2 × 1 matrix and B is a 1 × 2 matrix. Given that AB = 、 find BA.
2022-04-28