\int{(1-x)^{\frac{1}{5}}}dx=\int{t^{\frac{1}{5}}}\cdot{(-dt)}=-\int{t^{\frac{1}{5}}}dt=-\frac{t^{1+\frac{1}{5}}}{1+\frac{1}{5}}+C=-\frac{t^{\frac{6}{5}}}{\frac{6}{5}}+C