Given the curve f(x) = (5+ x^2 ) /
x
We need to calculate the area between the curve f(x), x=
1, and x= 2.
We know that the area under the curve f(x) is
the integral of f(x).
Let F(x) = intg
f(x).
Then the area is:
A =
F(2) - F(1).......(1).
Let us determine the
integral.
F(x) = intg (5+ x^2 )/x
dx
= intg ( 5/x + x)
dx
= intg (5/x) dx + intg x
dx
= 5*lnx + x^2
/2.
==> F(x) = 5lnx + x^2/2 +
C
==> F(2) = 5ln2 + 2 +
C.
==> F(1) = 5ln1 + 1/2 +
C
But we know that ln1 =
0.
==> F(1) = 1/2 +
C.
==> A = F(2) - F(1)
= 5ln2 + 2 - 1/2 = 5ln2 +
3/2
Then, the area between
f(x), x= 1,and x= 2 is:
A =
5ln2 + 3/2 square units.
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