Laplace transform of logarithm
Theorem. The Laplace transform of the natural logarithm
function
is
where is Euler’s gamma function.
Proof. We use the Laplace transform of the power function (http://planetmath.org/LaplaceTransformOfPowerFunction)
by differentiating it with respect to the parametre :
Setting here , we obtain
Q.E.D.
Note. The number is equal the of the Euler–Mascheroni constant (http://planetmath.org/EulersConstant), as is seen in the entry digamma and polygamma functions.