[填空题]
Consider the differenr (4 u4kxm7ktg lyi+)b/ mghz/y5zq-qtial equatix.o3v my5 8hgxon $\frac{\mathrm{d} y}{\mathrm{~d} x}+\frac{2 x^{3}}{1+x^{4}} y=4 x^{3} $ where y=1 when x=0 .
1. Show that $\sqrt{1+x^{4}} $ is an integrating factor for this differential equation.
2. Solve the differential equation giving your answer in the form y=f(x) .
