Here is the sketch of the two given functions.
The `y = sin(x) ` is plotted with a red color while `y = (2x)/pi` is plotted with a blue color.
As shown the graph, the two graphs intersect at the following points (approximately):
---> (-1.57 -1)
---> (0,0)
---> (1.57, 1).
The x-values from the intersection points will be used as the limits of integration or boundary values of x for each bounded region.
Using integration with respect to x, we follow the formula for the "Area between Two Curves" as:
A = `int_a^bf(x)-g(x)dx`
such that `f(x)gt=g(x)` for interval [a,b]
Or A =`int_a^b[y_(above)-y_(below)]dx`
Please see the attached file: "graph" to view how a typical approximating rectangle (sky blue in color) is used when using integration with respect to x. In the attached file, the width =dx and the height =f(x) such that
f(x)=` y_(above) - y_(below).`
To find the area of a bounded region, we will solve each bounded region with two separate integral then find the sum for the total bounded area/region.
In the first bounded region (yellow in shade), we have the `y_(above)= (2x)/pi`
and `y_(below) = sin(x)` with limits of integration from x =-1.57 to x=0.
`A_1=` `int_-1.57^0[(2x)/pi -sin(x)]dx`
=`[cos(x)+x^2/pi]|_(-1.57)^0`
= `[cos(0)+0^2/pi]-[cos(-1.57)+(-1.57)^2/pi]`
= [1+0] - [ 0.00079633+0.7846020385]
= 1 - 0.7853983685
`~~` 0.2146
In the second bounded region (pink in shade), we have the `y_(above)=sin(x)`
and `y_(below) = (2x)/pi` with limits of integration from x =0 to x=1.57.
`A_2` =`int_0^1.57[sin(x)-(2x)/pi]dx`
=`[-cos(x) - x^2/pi]|_0^(1.57)`
=`[-cos(1.57)-(1.57)^2/pi]-[-cos(0)-0^2/pi]`
= [ -0.00079633-0.7846020385] -[-1-0]
= - 0.7853983685+1
`~~` ` ` 0.2146
Notice that they are symmetrical about the origin.
We can multiply `A_1` by 2 since the two bounded area is the same.
Total Area= ``
= 0.2146 +0.2146
=0.4292
In the first bounded region (yellow in shade), we have the y_(above)= (2x)/pi
and y_(below) = sin(x) with limits of integration from x =-1.57 to x=1.
In the first bounded region (yellow in shade), we have the y_(above)= (2x)/pi
and y_(below) = sin(x) with limits of integration from x =-1.57 to x=1.
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