College of Science, Engineering and Technology
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MAT3700: Applied Mathematics
Assignment 04 — Semester 1, 2026
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MAT3700
Module Code:
Applied Mathematics
Module Name:
Assignment 04
Assignment:
2026
Due Date:
40
Total Marks:
Submitted in partial fulfilment of the requirements for MAT3700 — UNISA 2026
, UNISA | MAT3700 Assignment 04 — 2026
Question 1: Fourier Series of f (t) = t2 − t (15 marks)
Question: A periodic function f (t) with period 2π is defined by
f (t) = t2 − t, −π < t < π, f (t) = f (t + 2π).
Obtain a Fourier series expansion of the function.
Step 1: General Fourier series form
∞
a0 X
f (t) = + an cos nt + bn sin nt
2
n=1
where the coefficients are given by:
Z π Z π Z π
1 1 1
a0 = f (t) dt, an = f (t) cos nt dt, bn = f (t) sin nt dt.
π −π π −π π −π
Step 2: Compute a0
Z π Z π Z π
1 1
a0 = (t2 − t) dt = t2 dt − t dt
π −π π −π −π
t2 is an even function, so:
π π
π3 2π 3
Z Z
2
t dt = 2 t2 dt = 2 · =
−π 0 3 3
t is an odd function, so:
Z π
t dt = 0
−π
Therefore:
1 2π 3 2π 2
a0 = · =
π 3 3
a0 π2
=
2 3
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