exo7 6751

$\displaystyle \int_0^{2\pi}{dt\over a+\cos t}$ ($a>1$) ;

$\displaystyle \int_0^{2\pi}{dt\over (a+b\cos t)^2}$ ($a>b>0$) ;

$\displaystyle \int_0^{2\pi}{\cos^3{3t}\over 1-2a\cos t+a^2}\ dt$ ($a\in\C\setminus \{\pm 1\}$) ;

$\displaystyle \int_0^{2\pi}\exp{(\cos t)}\cos{(nt-\sin t)}\ dt$ ($n\in {\Zz}$).