8 15-4 Laplace transform of some simple time function 1. The unit step function () 1t>0 u(t) 0t<0 0 L{u()} e-stu(t)dt ∫ oO st SO§15-4 Laplace transform of some simple time function 1. The unit step function   − = 0 L{u(t)} e u(t)dt st      = 0 0 1 0 ( ) t t u t s u t 1 ( )  u(t) 1 0 t s s e st 1 0 =  − = −   − = 0 e dt st