Q. Evaluate ∫34x−52x2−15x+22dx. Write your answer in simplest form with all logs condensed into a single logarithm (if necessary).
Perform Polynomial Long Division: We need to evaluate the definite integral of the rational function (2x2−15x+22)/(x−5) from x=3 to x=4. To do this, we will first perform polynomial long division to simplify the integrand.
Split Integral into Two Parts: Performing the polynomial long division of (2x2−15x+22) by (x−5), we get:2x2−15x+22=(x−5)(2x+5)+(−3x+47)So, the integral becomes:∫34(2x+5−x−53x−47)dx
Integrate Polynomial Part: Now we can split the integral into two parts:∫34(2x+5)dx−∫34(x−53x−47)dxWe will integrate each part separately.
Integrate Rational Part: First, we integrate the polynomial part:∫34(2x+5)dx=[x2+5x]34Evaluating from x=3 to x=4, we get:(42+5⋅4)−(32+5⋅3)=(16+20)−(9+15)=36−24=12
Substitution Method: Next, we integrate the rational part:∫34(x−53x−47)dxTo integrate this, we will use the substitution method. Let u=x−5, then du=dx and x=u+5.The limits of integration also change: when x=3, u=−2; when x=4, u=−1.
Simplify the Integrand: Substituting x with u+5, the integral becomes:∫−2−1(u3(u+5)−47)duSimplify the integrand:∫−2−1(u3u+15−47)du=∫−2−1(u3u−32)duSplit the integral:∫−2−1(3−u32)du
Integrate Each Term: Now we integrate each term separately:∫−2−13du−∫−2−1(u32)duThe first integral is straightforward:∫−2−13du=[3u]−2−1=3(−1)−3(−2)=−3+6=3The second integral involves a natural logarithm:∫−2−1(u32)du=32⋅ln∣u∣ evaluated from u=−2 to u=−1.
Evaluate Logarithmic Part: Evaluating the logarithmic part, we get:32⋅ln∣u∣(−2)−1=32(ln∣−1∣−ln∣−2∣)=32(ln(1)−ln(2))Since ln(1)=0, this simplifies to:−32⋅ln(2)
Combine Results: Combining the results from the polynomial and rational parts, we get the final value of the definite integral:12 (from the polynomial part) −32×ln(2) (from the rational part)This is the final answer in its simplest form with the logarithm condensed.
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