Express the function f in terms of the unit step function an
     Express the function f in terms of the unit step function and its translations. Then find L(f).  f (x) = {4x, 0 lessthanorequalto x  
  
  Solution
f(x) = 4x( u(x) - u(x - 4) ) + 3( u(x - 4) ) , where u(x) denotes the step function
Taking Laplace Transform
L[ f(x) ](s) = (4/s2) - (4e-4s/s2) - (13e-4s/s)

