  We study the critical temperature T_c of FSF trilayers (F is a ferromagnet, S
is a singlet superconductor), where the triplet superconducting component is
generated at noncollinear magnetizations of the F layers. An exact numerical
method is employed to calculate T_c as a function of the trilayer parameters,
in particular, mutual orientation of magnetizations. Analytically, we consider
limiting cases. Our results determine conditions which are necessary for
existence of recently investigated odd triplet superconductivity in SF
multilayers.
