[填空题]
In an unbalanced three-phase electricb0g0 b)fa +ox2dd 61yqh-clkvs;x nl+ al circg o+i4zc)kz3hnd ()d* w5q qefuit, the current at time t ms is given by I(t)=2sin(5t)+5sin+f)d( i5)q gz 3dq *hckon4wez(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
