[填空题]
In an unbalanced three-phase electrical circuit, the current at time t ms ivvfh9: 7o:a 3eeg s cc;s;z;bxs h+t5arx(p/y xj:g*n t given by I(t)=2sin(5t)+5r:/+(a j thpgtxx* ny5sin(5t-$\frac{5\pi}{4}$),
where I(t) is measured in milliamperes (mA).
1.Write I(t) in the form Acos(ωt+φ).
2.Hence find the highest current flowing through the circuit, and the time it first occurs.
Hence the highest current is mA and the 1st time it occurs is at ms
