f(x) = x^2 + 5x - 3
Let F(x)
= integral f(x)
Then the area between f , x=1 and x= 2
is:
A = F(2) - F(1)
Then , let
us determine F(x) first.
F(x) = intg
f(x)
= intg (x^2 + 5x -3)
dx
= intg x^2 dx + intg 5x dx - intg 3
dx
= x^3/3 + 5x^2 /2 -
3x
F(2) = 8/3 + 20/2 -
6
= ( 16 + 60 - 36)/6 = 40/6 =
20/3
==> F(2) =
20/3
==> F(1) = 1/3 + 5/2 - 3 = (2 + 15 - 18)/6 =
-1/6
==> A = F(2) - F(1) = 20/3 - -1/6 =
41/6
Then the area = 41/6 square
units.
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