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calculate-1-1-ln-x-2-x-4-2-1-dx-




Question Number 47248 by maxmathsup by imad last updated on 06/Nov/18
calculate  ∫_(−1) ^1   ((ln(x+2))/((x+4)^2 −1))dx
calculate11ln(x+2)(x+4)21dx
Commented by maxmathsup by imad last updated on 16/Nov/18
let A = ∫_(−1) ^1  ((ln(x+2))/((x+4)^2 −1))dx ⇒ A =_(x+2=t)  ∫_1 ^3  ((ln(t))/((t+2)^2 −1))dt  =∫_1 ^3   ((ln(t))/((t+1)(t+3)))dt =(1/2)∫_1 ^3 {(1/(t+1)) −(1/(t+3))}ln(t)dt  =(1/2) ∫_1 ^3   ((ln(t))/(t+1))dt −(1/2) ∫_1 ^3   ((ln(t))/(t+3))dt   let determine ∫  ((ln(x))/(x+1))dx the calculator  give ∫ ((ln(x))/(x+1)) dx=ln(x)ln(x+1) +L_(i 2) (−x) ⇒  ∫_1 ^3   ((ln(t))/(t+1))dt =[ln(t)ln(t+1)+L_(i2) (−t)]_1 ^3 =2ln(3)ln(2) +L_(i2) (−3)  −L_(i2) (−1)  also  ∫  ((ln(x))/(x+3))dx =ln(x)ln((x/3)+1)+L_(i2) (−(x/3)) ⇒  ∫_1 ^3  ((ln(x))/(x+3)) =[ln(x)ln((x/3)+1)+L_(i2) (−(x/3))]_1 ^3   =ln(3)ln(2)+L_(i2) (−1)−L_(i2) (−(1/3))....
letA=11ln(x+2)(x+4)21dxA=x+2=t13ln(t)(t+2)21dt=13ln(t)(t+1)(t+3)dt=1213{1t+11t+3}ln(t)dt=1213ln(t)t+1dt1213ln(t)t+3dtletdetermineln(x)x+1dxthecalculatorgiveln(x)x+1dx=ln(x)ln(x+1)+Li2(x)13ln(t)t+1dt=[ln(t)ln(t+1)+Li2(t)]13=2ln(3)ln(2)+Li2(3)Li2(1)alsoln(x)x+3dx=ln(x)ln(x3+1)+Li2(x3)13ln(x)x+3=[ln(x)ln(x3+1)+Li2(x3)]13=ln(3)ln(2)+Li2(1)Li2(13).

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