Am atașat detalierea. :)) Sper că se înțelege.
Iar strict la chestia cu I(n):
[tex] \int\limits^0_1 { (1-x^3-1)(1-x^3)^n } \, dx = \\\\
\int\limits^0_1 { [(1-x^3)-1](1-x^3)^n } \, dx = \\\\
\int\limits^0_1 [ { (1-x^3)*(1-x^3)^n - 1*(1-x^3)^n } ] \, dx = \\\\
\int\limits^0_1 [{ (1-x^3)^{n+1} - (1-x^3)^n }] \, dx = \\\\
\int\limits^0_1 { (1-x^3)^{n+1}} - \int\limits^0_1 {(1-x^3)^n } \, dx = \\\\
I_{n+1} - I_n[/tex]
