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Question-141531




Question Number 141531 by sarkor last updated on 20/May/21
Commented by mohammad17 last updated on 20/May/21
let z^6 =x+1⇒6z^5 dz=dx    ∫  ((6z^3 (z^4 +z))/((z+1)))dz=6∫  ((z^7 +z^4 )/(z+1)))dz    =6∫z^4 (z^2 −z+1)dz=6((z^7 /7)−(z^6 /6)+(z^5 /5))+C    set:z=((x+1))^(1/6)     ∴∫  (((((x+1)^2 ))^(1/3) +((x+1))^(1/6) )/( (√(x+1))+((x+1))^(1/3) ))dx=(6/7)(((x+1)^7 ))^(1/6) −(x+1)+(6/5)(((x+1)^5 ))^(1/6) +C    by:⟨m.o⟩
$${let}\:{z}^{\mathrm{6}} ={x}+\mathrm{1}\Rightarrow\mathrm{6}{z}^{\mathrm{5}} {dz}={dx} \\ $$$$ \\ $$$$\int\:\:\frac{\mathrm{6}{z}^{\mathrm{3}} \left({z}^{\mathrm{4}} +{z}\right)}{\left({z}+\mathrm{1}\right)}{dz}=\mathrm{6}\int\:\:\frac{{z}^{\mathrm{7}} +{z}^{\mathrm{4}} }{\left.{z}+\mathrm{1}\right)}{dz} \\ $$$$ \\ $$$$=\mathrm{6}\int{z}^{\mathrm{4}} \left({z}^{\mathrm{2}} −{z}+\mathrm{1}\right){dz}=\mathrm{6}\left(\frac{{z}^{\mathrm{7}} }{\mathrm{7}}−\frac{{z}^{\mathrm{6}} }{\mathrm{6}}+\frac{{z}^{\mathrm{5}} }{\mathrm{5}}\right)+{C} \\ $$$$ \\ $$$${set}:{z}=\sqrt[{\mathrm{6}}]{{x}+\mathrm{1}} \\ $$$$ \\ $$$$\therefore\int\:\:\frac{\sqrt[{\mathrm{3}}]{\left({x}+\mathrm{1}\right)^{\mathrm{2}} }+\sqrt[{\mathrm{6}}]{{x}+\mathrm{1}}}{\:\sqrt{{x}+\mathrm{1}}+\sqrt[{\mathrm{3}}]{{x}+\mathrm{1}}}{dx}=\frac{\mathrm{6}}{\mathrm{7}}\sqrt[{\mathrm{6}}]{\left({x}+\mathrm{1}\right)^{\mathrm{7}} }−\left({x}+\mathrm{1}\right)+\frac{\mathrm{6}}{\mathrm{5}}\sqrt[{\mathrm{6}}]{\left({x}+\mathrm{1}\right)^{\mathrm{5}} }+{C} \\ $$$$ \\ $$$${by}:\langle{m}.{o}\rangle \\ $$$$ \\ $$

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