Write Integral: Write down the integral to be solved.I=∫−xcos(−2x+6)dx
Use Substitution: Use substitution to simplify the integral. Let u=−2x+6, then du=−2dx. We need to express dx in terms of du, so dx=−2du. Also, when u=−2x+6, x=26−u.I=∫−(26−u)cos(u)(−2du)
Simplify Integral: Simplify the integral by distributing the constants.I=∫(41)(6−u)cos(u)duI=(41)∫6cos(u)du−(41)∫ucos(u)du
Split and Solve: Split the integral into two parts and solve each part separately.First part: (41)∫6cos(u)duSecond part: −41∫ucos(u)du
Integrate First Part: Integrate the first part using the basic integral of cos(u).First part: (1/4)∫6cos(u)du=(1/4)(6sin(u))+C1
Integrate Second Part: Integrate the second part using integration by parts. Let v=u and dw=cos(u)du. Then dv=du and w=sin(u). Second part: -\frac{\(1\)}{\(4\)}\int u\cos(u) du = -\frac{\(1\)}{\(4\)}(u\sin(u) - \int \sin(u) du) = -\frac{\(1\)}{\(4\)}(u\sin(u) + \cos(u)) + C_2
Combine Results: Combine the results from step \(5 and step 6.I=(41)(6sin(u))−(41)(usin(u)+cos(u))+C
Substitute Back: Substitute back u=−2x+6 into the integral.I=41(6sin(−2x+6))−41((−2x+6)sin(−2x+6)+cos(−2x+6))+C
Final Simplification: Simplify the expression. I=23sin(−2x+6)+21xsin(−2x+6)−41cos(−2x+6)+C
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