[填空题]
Two voltage sources are connectea 3 6c6hau4oqed to a circuit. At t6rq-e2qj anl 70)*xy ;z1w qlkrz7gel ime t milliseconds (ms), the voltage from the first so rey1x q 2jzz g0;leqnlq-*klrw7a6 7)urce is $V_1$(t)=12cos(20t) and the voltage from the second source is $V_2$(t)=18cos(20t+5), shere both $V_1$(t) and $V_2$(t) are
easured in volts.
1.Write, in the form V(t)=Acos(ωt+φ), an expression for the total voltage in the circuit at time t ms.
2.Hence write down the highest voltage in the circuit.
Hence the highest voltage in the circuit is volts
