Given the curve f(x) =
(2x^2-5)/x
We need to find the integral of f(x) between 1
and 2.
Let F(x) = Int
f(x).
Then the definite integral is
:
A = F(2) - F(1)
Let us
determine F(x).
==> F(x) = Int f(x) dx =
(2x^2-5)/x dx
We will
simplify.
==> F(x) = Int (2x^2/x) dx - Int 5/x
dx
==> F(x) = Int 2x dx - 5*Int
dx/x
==> F(x) = 2x^2/2 - 5*ln x +
C
==> F(x) = x^2 - 5lnx +
C
==> F(1) = 1- 5ln1 + c =
1
==> F(2) = 4-5ln2 +
C
==> A = 4-5ln2 - 1 = 3-5ln2 = -0.47 (
approx.)
Then the definite integral is 3-5ln2
= -0.47.
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