Animated Solution for Mathematics - Definite Integration: The area of the region enclosed by the curves y=x2−4x+4 and y2=16−8x is:
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Visualized Solution
y=x2−4x+4
Given equation: y=x2−4x+4
Recognize the perfect square: y=(x−2)2
This represents an upward-opening parabola.
The vertex is at (2,0).
y2=16−8x
Given equation: y2=16−8x
Factor out −8: y2=−8(x−2)
This represents a leftward-opening parabola.
The vertex is also at (2,0).
Intersection Equation
To find where they meet, solve the equations simultaneously.
From the first curve: y=(x−2)2
Substitute into the second: ((x−2)2)2=−8(x−2)
(x−2)4=−8(x−2)
Solve for x
Rearrange: (x−2)4+8(x−2)=0
Factor out (x−2): (x−2)[(x−2)3+8]=0
Case 1: x−2=0⟹x=2
Case 2: (x−2)3=−8⟹x−2=−2⟹x=0
Intersection Coordinates
For x=2, y=(2−2)2=0. Point: (2,0)
For x=0, y=(0−2)2=4. Point: (0,4)
These are the two points bounding our region.
Enclosed Region
The area is bounded between x=0 and x=2.
Upper boundary (yU): y=16−8x
Lower boundary (yL): y=(x−2)2
Area Integral
Area A=∫ab(yU−yL)dx
A=∫02(16−8x−(x−2)2)dx
We can split this into two separate integrals.
First Integral I1
I1=∫0216−8xdx
Let u=16−8x, then du=−8dx⟹dx=−8du
Limits: x=0⟹u=16, x=2⟹u=0
I1=∫160u(−8du)=81∫016u1/2du
Compute I1
I1=81[3/2u3/2]016
I1=81⋅32[163/2−0]
163/2=(16)3=43=64
I1=121⋅64=316
Compute Second Integral I2
I2=∫02(x−2)2dx
Let v=x−2, dv=dx. Limits: −2 to 0.
I2=∫−20v2dv=[3v3]−20
I2=0−(3−8)=38
Final Area
Total Area A=I1−I2
A=316−38
A=38 square units.
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The Sigma Insight: Area Bounded by Curves
Solution Diagram
Analyzing the Setup
Imagine you are standing at the point (2,0) on a Cartesian plane. You look up and see a graceful curve, a parabola opening upwards, defined by y=(x−2)2.
You turn your head and see another curve, a parabola opening to the left, defined by y2=−8(x−2). These two curves are partners in a dance, enclosing a beautiful, finite region. Our goal is to find the area of this region.
The Algebraic Shortcut
To find the area, we first need to know where these curves meet. We set up the intersection equation by substituting y=(x−2)2 into y2=−8(x−2).
This gives us:
((x−2)2)2=−8(x−2)
This simplifies to (x−2)4=−8(x−2). A common mistake here is to expand the fourth power; instead, bring everything to one side:
(x−2)4+8(x−2)=0
Now, factor out (x−2) to get (x−2)((x−2)3+8)=0. This reveals our intersection points: x=2 and (x−2)3=−8, which means x−2=−2, so x=0. These are the boundaries of our integral.
The Calculus Bridge
Now that we have our limits, we need to set up the integral for the area. The area A is the integral of the upper curve minus the lower curve from x=0 to x=2.
The upper boundary is the horizontal parabola y=−8(x−2)=16−8x, and the lower boundary is the vertical parabola y=(x−2)2. So, our integral is:
A=∫02(16−8x−(x−2)2)dx
We can split this into two parts: I1=∫0216−8xdx and I2=∫02(x−2)2dx.
The Final Calculation
For I1, we use substitution. Let u=16−8x, then du=−8dx. The limits change from x=0 to u=16 and x=2 to u=0.