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Evaluate:`int(x^2-1)/((x^4+3x^2+1)tan^(-1)(x+1/x))dx` |
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Answer» `I=int(x^(2)-1)/((x^(4)+3x^(2)+1)tan^(-1)(x+(1)/(x)))dx` `=int(1-(1)/(x^(2)))/((x^(2)+(1)/(x^(2))+3)tan^(-1)(x+(1)/(x)))dx` Put `x+(1)/(x)=t` ` :. (1-(1)/(x^(2)))dx=dt " and " x^(2)+(1)/(x^(2))+3=t^(2)+1` ` :. I=int(dt)/((t^(2)+1)tan^(-1)t)="In"|tan^(-1)t|+C` `="In"|tan^(-1)(x+(1)/(x))|+C` |
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