Q. The diagram shows the curve y=x2−3x+1 and the line y=5.Find the area of the shaded region. Give your answer as a fraction in its simplest form.
Set Intersection Points: To find the area of the shaded region, we need to calculate the definite integral of the difference between the line y=5 and the curve y=x2−3x+1 from the left intersection point to the right intersection point.
Calculate Integral: First, find the points of intersection by setting the equations equal to each other: x2−3x+1=5.
Find Roots: Solve the equation x2−3x+1=5 by subtracting 5 from both sides to get x2−3x−4=0.
Set Up Integral: Factor the quadratic equation: (x−4)(x+1)=0.
Integrate Function: Find the roots of the equation by setting each factor equal to zero: x−4=0 and x+1=0, which gives us x=4 and x=−1.
Evaluate Integral: The points of intersection are x=−1 and x=4. Now, set up the integral from −1 to 4 of the function 5−(x2−3x+1).
Upper Limit Calculation: The integral becomes ∫−14(4−x2+3x)dx.
Lower Limit Calculation: Integrate the function: ∫(4−x2+3x)dx=4x−31x3+23x2.
Subtract Values: Evaluate the integral from −1 to 4: [4x−(1/3)x3+(3/2)x2] from −1 to 4.
Subtract Values: Evaluate the integral from −1 to 4: [4x−(1/3)x3+(3/2)x2] from −1 to 4.Plug in the upper limit of the integral: 4(4)−(1/3)(4)3+(3/2)(4)2=16−(1/3)(64)+(3/2)(16).
Subtract Values: Evaluate the integral from −1 to 4: [4x−(1/3)x3+(3/2)x2] from −1 to 4.Plug in the upper limit of the integral: 4(4)−(1/3)(4)3+(3/2)(4)2=16−(1/3)(64)+(3/2)(16).Calculate the value for the upper limit: 16−64/3+24=48/3−64/3+72/3=56/3.
Subtract Values: Evaluate the integral from −1 to 4: [4x−(1/3)x3+(3/2)x2] from −1 to 4.Plug in the upper limit of the integral: 4(4)−(1/3)(4)3+(3/2)(4)2=16−(1/3)(64)+(3/2)(16).Calculate the value for the upper limit: 16−64/3+24=48/3−64/3+72/3=56/3.Plug in the lower limit of the integral: 4(−1)−(1/3)(−1)3+(3/2)(−1)2=−4−(1/3)(−1)+(3/2)(1).
Subtract Values: Evaluate the integral from −1 to 4: [4x−(1/3)x3+(3/2)x2] from −1 to 4.Plug in the upper limit of the integral: 4(4)−(1/3)(4)3+(3/2)(4)2=16−(1/3)(64)+(3/2)(16).Calculate the value for the upper limit: 16−64/3+24=48/3−64/3+72/3=56/3.Plug in the lower limit of the integral: 4(−1)−(1/3)(−1)3+(3/2)(−1)2=−4−(1/3)(−1)+(3/2)(1).Calculate the value for the lower limit: −4+1/3+3/2=−12/3+1/3+4.5/3=−6.5/3.
Subtract Values: Evaluate the integral from −1 to 4: [4x−(1/3)x3+(3/2)x2] from −1 to 4.Plug in the upper limit of the integral: 4(4)−(1/3)(4)3+(3/2)(4)2=16−(1/3)(64)+(3/2)(16).Calculate the value for the upper limit: 16−64/3+24=48/3−64/3+72/3=56/3.Plug in the lower limit of the integral: 4(−1)−(1/3)(−1)3+(3/2)(−1)2=−4−(1/3)(−1)+(3/2)(1).Calculate the value for the lower limit: −4+1/3+3/2=−12/3+1/3+4.5/3=−6.5/3.Subtract the lower limit value from the upper limit value: 56/3−(−6.5/3)=56/3+6.5/3=62.5/3.
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