Вычислить интеграл dx/(cos^(4)x

[latex] int {sec^m(x)} , dx =[/latex]  (sin(x) sec^(m-1)(x))/(m-1) + (m-2)/(m-1) [latex] int {sec^(-2+m) (x)} , dx [/latex]где m=4 == 1/3 tan(x) sec^2(x)+2/3 [latex] int {sec^2(x)} dx [/latex] == (2 tan(x))/3+1/3 tan(x) sec^2(x)+constant