Solve the given differential equations (Q. 6 & Q. 39) using the Integration Factor technique. Explain or show your method of solution. 6. di + idt = e-tcostdt [Hint: dy + Pydx = Qdx and ye Pax = [ QefPax dx+C] [ans. : i = et(sint + c) amps] 39. The electric current; i, in a circuit with a voltage; V, resistance; R, and inductance; L, is a function of the time t given by ~ + hi = - . Solve for / as a function of t if the initial current lo = i(t) = 0. R + ans. : i = - (1 - e it) amps