Indefinite Integration

$-\left(x^4+1\right)^{\frac{1}{4}}+\mathrm{c}$, (where c is a constant of integration)

$\left(x^4+1\right)^{\frac{1}{4}}+\mathrm{c},($ where c is a constant of integration)

$\left(1+\frac{1}{x^4}\right)^{\frac{1}{4}}+\mathrm{c}$, (where c is a constant of integration)

$-\left(1+\frac{1}{x^4}\right)^{\frac{1}{4}}+\mathrm{c}$, (where c is a constant of integration)