Q. Evaluate ∫34x−24x2−9x+1dx. Write your answer in simplest form with all logs condensed into a single logarithm (if necessary).Submit Answer
Identify Integral: Identify the integral to be evaluated.We need to evaluate the integral of the function (4x2−9x+1)/(x−2) from x=3 to x=4.
Polynomial Long Division: Perform polynomial long division.Before integrating, we should simplify the integrand by performing polynomial long division of (4x2−9x+1) by (x−2).
Carry Out Division: Carry out the long division.Dividing 4x2 by x gives 4x. Multiply (x−2) by 4x to get 4x2−8x. Subtract this from the original numerator to get −9x+1−(−8x)=−x+1. Dividing −x by x gives −1. Multiply (x−2) by −1 to get x2. Subtract this from x3 to get −1. So the quotient is x5 with a remainder of −1.
Rewrite Integral: Rewrite the integral with the result of the division.The integral can now be written as the integral of 4x−1 plus the integral of the remainder −1 divided by (x−2), from x=3 to x=4.∫(4x−1)dx+∫(x−2)−1dx from x=3 to x=4.
Integrate First Part: Integrate the first part of the expression.The integral of 4x−1 with respect to x is 2x2−x. We will evaluate this from x=3 to x=4.
Integrate Second Part: Integrate the second part of the expression.The integral of −x−21 with respect to x is −ln∣x−2∣. We will evaluate this from x=3 to x=4.
Evaluate Definite Integrals: Evaluate the definite integrals.First, evaluate 2x2−x from x=3 to x=4:(2(4)2−4)−(2(3)2−3)=(2×16−4)−(2×9−3)=(32−4)−(18−3)=28−15=13.Next, evaluate −ln∣x−2∣ from x=3 to x=4:(−ln∣4−2∣)−(−ln∣3−2∣)=(−ln∣2∣)−(−ln∣1∣)=−ln(2)−(−ln(1))=−ln(2)−0=−ln(2).
Combine Results: Combine the results.The value of the integral is the sum of the results from steps 7 and 8:13−ln(2).
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