Q. Use the graph of the integrand to evaluate the integral.∫−11(1+1−x2)dx
Identify Function & Limits: Identify the function to integrate and the limits of integration. The function to integrate is f(x)=1+1−x2, and the limits of integration are from −1 to 1.
Geometric Interpretation: Recognize the geometric interpretation of the integral. The function 1−x2 represents a semicircle with radius 1 centered at the origin. The integral of this function from −1 to 1 is the area of the semicircle. Adding 1 to the function raises the semicircle by 1 unit, creating a shape that includes the semicircle and a rectangle below it.
Calculate Semicircle Area: Calculate the area of the semicircle.The area of a full circle with radius 1 is π(1)2=π. Since we only have a semicircle, its area is π/2.
Calculate Rectangle Area: Calculate the area of the rectangle.The rectangle has a width of 2 (from −1 to 1) and a height of 1. Therefore, its area is 2×1=2.
Find Total Area: Add the areas of the semicircle and the rectangle to find the total area under the curve.The total area under the curve from −1 to 1 is the area of the semicircle plus the area of the rectangle, which is π/2+2.
Write Final Answer: Write the final answer.The definite integral of the function 1+1−x2 from −1 to 1 is π/2+2.
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