Graph each equation to determine the bounded region.
( Red curve is the graph of `y=e^x` . Blue curve is the graph of `y=xe^x` . And green line is the graph of x=0.)
Base on the graph, the bounded region of the three equations starts at x=0 and ends at x =1. Then, draw a vertical strip inside the region. Apply the formula:
`A=int_a^b (y_U - y_L)dx`
(Refer to the attached figure below.)
The upper...
Graph each equation to determine the bounded region.
( Red curve is the graph of `y=e^x` . Blue curve is the graph of `y=xe^x` . And green line is the graph of x=0.)
Base on the graph, the bounded region of the three equations starts at x=0 and ends at x =1. Then, draw a vertical strip inside the region. Apply the formula:
`A=int_a^b (y_U - y_L)dx`
(Refer to the attached figure below.)
The upper end of the vertical strip touches the curve `y =e^x` . And its lower end touches the curve `y=xe^x` . So the integral will be:
`A=int_0^1 (e^x - xe^x) dx`
`A = int_0^1 e^x(1-x)dx`
To take the integral of this, apply integration by parts `int udv = u*v - int vdu` .
In the integrand of area, u , du , v and dv are:
`u=1-x`
`du=-dx`
`dv=e^xdx`
`v=e^x`
Plugging them to the formula integration by parts, then A becomes:
`A = (1-x)*e^x - int e^x *(-dx) = (1-x)e^x + int e^x dx`
`A = ((1-x)e^x + e^x )|_0^1 = (e^x-xe^x + e^x)_0^1 `
`A = (2e^x - xe^x )|_0^1`
`A= (2e^1-1*e^1) - (2e^0-0*e^0)`
`A= e -2`
`A=0.72`
Therefore, the area of the bounded region is 0.72 square units.
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