Integrate the functions`e^(3logx)(x^4+1)^(-1)`

1.	Integrate the functions`e^(3logx)(x^4+1)^(-1)`
Answer» I `= int e^(3log x) (x^2 + 1)^-1 dx` `= int e^(log x^3) 1/(x^2+1) dx` `= x^3/(x^4 + 1) dx` let `x^4 + 1 = t` `4x^3 dx = dt` `x^3dx = dt/4` `int (dt/4)/t` `= 1/4 int dt/t` `=1/4 log \|t\|` `= 1/4 log\|x^4+1\| + c` answer

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