Chapter 4 Problem solution 4. 15 Let x(t) be a signal with Fourier transform x(ja).Suppose we are given the following facts: (1). x(t)is real (2)-x(t)=0ort≤0 (32-Refx(io)felo do=ite" Determine a closed-form expression for x(t) x(t)=2te u(t) 77 Chapter 4 Problem Solution 4.15 Let be a signal with Fourier transform . Suppose we are given the following facts: (1). is real. (2). for . (3). Determine a closed-form expression for . x(t) X(j) x(t) x(t)= 0 t  0  ( ) 1 Re 2 j t t X j e d t e     + − − =  x(t) x(t) te u(t) −t = 2