Evaluate: ∫((x^2+1))/((x^4+1) ) dx

Asked by Manoj | 9th Mar, 2013, 07:32: AM

Expert Answer:

I denotes for the value of integral.


Divide numerator and denominator by x2, we get:


(1+1/x2)/[(x-1/x)+2]    as x2+1/x2 = (x-1/x)+2

Let (x-1/x)=t so dt=(1+1/x)dx

Therefore, the integral becomes

I = dt/(t+2)

1/(2)1/2  tan-1t/(2)1/2 +c   

Now, substitute value of t in above to get the answer.

Answered by  | 10th Mar, 2013, 03:54: PM

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