a)Eq:FM 
V=4.000000*sin(157079632.679490*t+25.000000*sin(2513.274123)*t)

 b)Eq:PM 
V=4.000000*sin(157079632.679490*t+25.000000*sin(2513.274123)*t)

 c)Eq:FM 
V=4.000000*sin(157079632.679490*t+5.000000*sin(12566.370614)*t)

 d)Eq:FM 
V=4.000000*sin(157079632.679490*t+25.000000*sin(12566.370614)*t) 
 Execution done.