Which technique is best to evaluate ∫1x4+1dx\int \frac{1}{x^4+1} dx∫x4+11dx?
Integration by parts
Partial fraction decomposition using x4+1=(x2+1)2−2x2x^4+1 = (x^2+1)^2 - 2x^2x4+1=(x2+1)2−2x2
Trigonometric substitution x=tanθx = \tan \thetax=tanθ
Substitution u=x2u = x^2u=x2