Question 1
[25]
1.1 Consider the circuit as shown in the below figure with a 30 resistor and a 1-H inductor.
1.1.1 Write down the differential equation of the circuit where current i is flowing clockwise.
(2)
1.1.2 Solve the differential equation for the current as a function of time.
(5)
1.1.3 Determine the current as a function of time in this circuit given that its initial value is 6 A
(3)
1.2 Solve the differential equation (y2-x} dx + 2ydy =O
(10}
1.3 Find the general solution of the differential equation.
-d+x t2x =0
(5}
dt
Question 2
[25]
2.1 A SOgmass attached to a spring, moving in air with initial conditions y (O}= 4 cm and
y' (O)= 40 cm/s. The spring is such that a 30 g mass stretches it 6 cm. Approximate the
acceleration of gravity is 1000 cm/s 2•
Formulate the differential equation and find the movement of the mass position at any time t. (10)
2.2 Find the general solution of x" -3x' +2x = 2t2 +1
2.3 Find a particular solution of x" -x = 3e-t
Question 3
3.1 Use matrices to find the solution for the set of equation as given below
(10}
(5)
[25]
(10}
4x + 8y + z =-6
2x-3y + 2z = 0
X + 7y-3z =-8
3.2 Find the eigen values of the matrix A given as
(10}
=~ ) A=(~
6 -6 4
3.3 Find kif
(5)
[k; A=
2
k
+1
]
2
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