Q. Evaluate ∫14x−74x2−27x−5dx. Write your answer in simplest form with all logs condensed into a single logarithm (if necessary).
Perform Polynomial Long Division: Perform polynomial long division to simplify the integrand.We need to divide the polynomial 4x2−27x−5 by x−7.
Polynomial Long Division Calculation: Polynomial long division calculation. Dividing 4x2 by x gives 4x. Multiplying (x−7) by 4x gives 4x2−28x. Subtracting this from 4x2−27x gives x−5. Dividing x by x gives x0. Multiplying (x−7) by x0 gives x3. Subtracting this from x−5 gives x5. So the division gives us x6 with a remainder of x5.
Rewrite Integral with Result: Rewrite the integral with the result of the division.The integral becomes:∫(4x+1)dx+∫(x−72)dx from 1 to 4.
Integrate First Part: Integrate the first part of the integral.The integral of 4x+1 with respect to x is 2x2+x.
Integrate Second Part: Integrate the second part of the integral.The integral of x−72 with respect to x is 2ln∣x−7∣.
Combine and Evaluate Definite Integral: Combine the results and evaluate the definite integral from 1 to 4. The integral from 1 to 4 is: (2x2+x)+2ln∣x−7∣ evaluated from 1 to 4.
Evaluate Antiderivative at Upper Limit: Evaluate the antiderivative at the upper limit x=4. Plugging in x=4 gives us: (2(4)2+4)+2ln∣4−7∣=(2(16)+4)+2ln∣−3∣=(32+4)+2ln(3)=36+2ln(3).
Evaluate Antiderivative at Lower Limit: Evaluate the antiderivative at the lower limit x=1. Plugging in x=1 gives us: (2(1)2+1)+2ln∣1−7∣=(2(1)+1)+2ln∣−6∣=(2+1)+2ln(6)=3+2ln(6).
Subtract Lower Limit from Upper Limit: Subtract the value at the lower limit from the value at the upper limit.(36+2ln(3))−(3+2ln(6))=33+2ln(3)−2ln(6).
Simplify Using Properties of Logarithms: Simplify the expression using properties of logarithms. 2ln(3)−2ln(6) can be simplified using the quotient rule of logarithms: ln(a)−ln(b)=ln(ba).So, 2ln(3)−2ln(6)=2ln(63)=2ln(21).
Combine Logarithms into Single Logarithm: Combine the logarithms into a single logarithm.The final answer is 33+2ln(21).
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