Найти интегралы [latex] \int\limits {(3-2ctg^2x)/cos^2x} \, dx \int\limits {x^4/1+x^2} \, dx [/latex]

[latex]\int \frac{3-2ctg^2x}{cos^2x} dx=\int \frac{3dx}{cos^2x}-2\int \frac{ctg^2x}{cos^2x}dx=\\\\=3tgx-2\int \frac{dx}{sin^2x}=3tgx+2ctgx+C\\\\\\\int \frac{x^4}{x^2+1}dx=\int (x^2-1+\frac{1}{x^2+1})dx=\int x^2dx-\int dx+\int \frac{dx}{x^2+1}=\\\\\frac{x^3}{3}-x+arctgx+C[/latex]