Q. What is the area of the region between the graphs of f(x)=x2+2x and g(x)=2x+1 ?Choose 1 answer:(A) 32(B) 2(C) 34(D) 310
Set Equations Equal: To find the area between the two curves, we first need to find the points of intersection by setting f(x) equal to g(x).
Solve for x: Set f(x)=g(x): x2+2x=2x+1.
Calculate Limits of Integration: Subtract 2x from both sides to simplify the equation: x2=1.
Set up Integral: Take the square root of both sides to find the values of x: x=±1.
Substitute Functions: The points of intersection are x=−1 and x=1. These will be the limits of integration to find the area between the curves.
Simplify Integrand: Set up the integral to calculate the area: A=∫−11(g(x)−f(x))dx.
Integrate Function: Substitute the functions into the integral: A=∫−11((2x+1)−(x2+2x))dx.
Evaluate Upper Limit: Simplify the integrand: A=∫−11(1−x2)dx.
Evaluate Lower Limit: Integrate the function: A=[x−(31)x3] from −1 to 1.
Find Total Area: Evaluate the integral at the upper limit: A(1)=1−(31)(1)3=1−31=32.
Final Answer: Evaluate the integral at the lower limit: A(−1)=−1−31(−1)3=−1+31=−32.
Final Answer: Evaluate the integral at the lower limit: A(−1)=−1−(31)(−1)3=−1+31=−32.Find the difference between the two evaluations to get the total area: A=A(1)−A(−1)=32−(−32)=32+32=34.
Final Answer: Evaluate the integral at the lower limit: A(−1)=−1−(1/3)(−1)3=−1+1/3=−2/3.Find the difference between the two evaluations to get the total area: A=A(1)−A(−1)=2/3−(−2/3)=2/3+2/3=4/3.The area of the region between the graphs of f(x) and g(x) is 4/3, which corresponds to answer choice (C).