Animated Solution for Mathematics - Definite Integration: If the area of the region {(x,y):∣x2−2∣≤y≤x} is A, then 6A+162 is equal to ______________
Enter Numerical Value:
Visualized Solution
Visualizing the Bounded Region
Identify the region: {(x,y):∣x2−2∣≤y≤x}
Upper boundary: y=x
Lower boundary: y=∣x2−2∣
Analyzing the Absolute Value
The function y=∣x2−2∣ changes behavior at x2=2.
Case 1: y=2−x2 when x<2
Case 2: y=x2−2 when x≥2
Finding the First Intersection
For x<2, equate the boundaries: 2−x2=x
Rearranging gives: x2+x−2=0
Factorizing: (x+2)(x−1)=0
Valid intersection point: (1,1)
Finding the Second Intersection
For x≥2, equate the boundaries: x2−2=x
Rearranging gives: x2−x−2=0
Factorizing: (x−2)(x+1)=0
Valid intersection point: (2,2)
Setting up the Area Integral
The total area A is the integral of (Upper - Lower) from x=1 to x=2.
A=∫12(x−∣x2−2∣)dx
Splitting the Integral Domain
Split the integral at the critical point x=2.
I1=∫12(x−(2−x2))dx=∫12(x2+x−2)dx
I2=∫22(x−(x2−2))dx=∫22(−x2+x+2)dx
Evaluating the First Integral
Integrate I1: [3x3+2x2−2x]12
Substitute upper limit: 322+1−22
Substitute lower limit: 31+21−2=−67
I1=613−342
Evaluating the Second Integral
Integrate I2: [−3x3+2x2+2x]22
Substitute upper limit: −38+2+4=310
Substitute lower limit: −322+1+22
I2=37−342
Combining the Area Components
Total Area A=I1+I2
A=(613−342)+(614−342)
A=627−382=29−382
Final Expression Calculation
We need to find the value of 6A+162.
Substitute A: 6(29−382)+162
Expand: 27−162+162
Final Answer: 27
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The Sigma Insight: Area Bounded by Curves
Solution Diagram
Analyzing the Setup
Imagine you are standing on the Cartesian plane, looking at two distinct mathematical entities: a simple, elegant line y=x and a more complex, mirrored parabola y=∣x2−2∣. Your task is to find the area trapped between them.
The function y=∣x2−2∣ is a classic 'W' shape, formed by taking the parabola y=x2−2 and reflecting its negative portion above the x-axis. The line y=x cuts through this shape, creating a bounded region that we must measure.
The Algebra of Intersections
Before we can integrate, we must know where our region begins and ends. We look for the intersection points by equating the two functions.
For the left side of the modulus, where x<2, we solve 2−x2=x, which simplifies to x2+x−2=0. Factoring this, we find (x+2)(x−1)=0. Since our region is in the first quadrant, we discard x=−2 and keep x=1.
For the right side, where x≥2, we solve x2−2=x, leading to x2−x−2=0. Factoring this gives (x−2)(x+1)=0. Again, we discard the negative root and keep x=2. Our boundaries are set: x=1 to x=2.
The Calculus of the Modulus
Now, we set up our integral for the area A=∫12(x−∣x2−2∣)dx. The modulus is the gatekeeper here; it changes its definition at x=2.
We must split the integral into two parts:
I1=∫12(x−(2−x2))dx
I2=∫22(x−(x2−2))dx
For I1, we integrate x2+x−2, yielding:
[3x3+2x2−2x]12
Substituting the limits, we find I1=613−342.
For I2, we integrate −x2+x+2, yielding:
[−3x3+2x2+2x]22
Substituting these limits, we find I2=37−342.
The Final Reveal
Combining these, we get:
A=I1+I2=29−382
The final step is to evaluate the expression 6A+162. Substituting our value for A, we get:
6(29−382)+162
Distributing the 6, we get 27−162+162. The irrational terms cancel out with beautiful precision, leaving us with the final answer: 27.