A simple algorithm for finding the exponent and real logarithm of a real square matrix of the second order is presented, in which it is not required to reduce it to Jordan form. The method of such calculation of the exponent of a given matrix, proposed by A.F. Filippov, also applies to its algorithm, the set of which may be empty, single-element, and infinite — countable and even continuous.
I. N. Sergeev (Wed,) studied this question.