To calculate the definite integral of the given function,
we'll use the substitution method.
We'll calculate Integral
of f(x) = x^2/(x^2 - 6x + 10)
We notice that if we'll
complete the numrator, we'll obtain the denominator, x^2 - 6x + 10, so, we'll subtract
and add 6x and we'll add and subtract 10.
The numerator
will become:
x^2 - 6x + 10 + 6x -
10
The integral will
become:
Int (x^2- 6x + 10 + 6x - 10)dx/(x^2 - 6x +
10)
We'll re-write the integral, using the addition
property of integrals:
Int (x^2- 6x + 10)dx/(x^2 - 6x +
10)+Int (6x - 10)dx/(x^2 - 6x + 10)
We'll solve the first
integral:
Int (x^2- 6x + 10)dx/(x^2 - 6x + 10) = Int dx = x
+ C
We'll solve the second
integral:
Int (6x - 10)dx/(x^2 - 6x +
10)
We'll create the square (2x-3)^2 to the
denominator.
x^2 - 6x + 10 = (2x-3)^2 +
31
We'll note 2x-3= t.
We'll
write the numerator in t:
2x-3=
t
2x = t+3
x =
(t+3)/2
6(t+3)/2 - 10 = 3(t+3) -
10
We'll remove the
brackets:
3t+9-10
The
numerator will become:
6x - 10 =
3t-1
We'll re-write the integral in
t:
Int (6x - 10)dx/[(2x-3)^2 + 31] = Int (3t-1)dt/(t^2 +
31)
Int (3t-1)dt/(t^2 + 31) = 3Int dt/(t^2 + 31) - Int
dt/(t^2 + 31)
3Int dt/(t^2 + 31) = 6/2 ln (t^2 + 31) +
C
Int dt/(t^2 + 31) = (2/sqrt31)*arctan
(1/sqrt31)
Int f(x)dx = 1/3 + 3ln (32/31) -
(2/sqrt31)*arctan (1/sqrt31)
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