Your Daily Experience of Math Adventures
We like to evaluate the integral:
where n = 1, 2, 3, 4.
We employ the technique of Partial Fractions. This algebraic
method is assumed to be known.
When n = 1,
When n = 2,
By using the substitution x = tan q, it is a simple
exercise to get:
Then,
In getting (3) here, we change the variable
and apply (2).
Alternatively, you can start by using the substitution
x = a tan q at the beginning of (3).
When n = 3,
Finally you may check by changing the valuable suitably:
When n = 4,
Since x4 + 1 cannot be factorized under rational numbers,
we start with the factorization :
x4 + 1 = (x4 + 2x2 + 1) – 2x2 =
(x2 + 1)2 – (Ö2 x)2 = (x2 + Ö2 x + 1)(x2 -Ö2 x +1)
As a Partial Fraction exercise, we get:
Finally, if you still feel energetic of checking, we arrive:
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