Question 1
[25]
1.1 The law of decay states that the rate of decay for a radioactive material is proportional to the
number of atoms present.
1.1.1 Formulate the differential equation and determine the amount of radioactive material left
at any time, t by solving the differential equation.
(5)
1.1.2 Determine the half-life of a radioactive material using solution of differential equation. (5)
1.1.3 In two years, 3 g of a radioisotope decay to 0.9 g. Determine both the half-life T and the
decay rate k.
(5)
1.2 Solve the equation,
= -ddx+t t 2x Cost
(5)
1.3 Solve the differential equation (2xy-3x2) dx + (x2-2y) dy = O
(5)
Question 2
[25]
2.1 Suppose that a car is going 76 m/s when brakes are applied at t = 2 s. Suppose that the
nonconstant deceleration is known to be a= -12t 2. Formulate the differential equation
and determine the distance the car travels.
(10)
2.2 Find the particular solution of x' +x = e·1
(10)
2.3 Solve the equation: 5yll +2yl +2y = o.
(5)
Question 3
[25]
3.1 Find the eigenvalues and eigenvector of the matrix A given by
-1
2
-1
3.2 Solve the following system of equations using Gauss-Jordan Elimination:
-3x - 2y + 4z = 9
3y- 2z = 5
4x - 3y+ 2z = 7
3.3
! If [ 2x 3 ] [~ 3] [;] = 0, find the value of x
(10)
(10)
(5)
2