Express the current as a time waveform i$($t$)=$ A$$ cos$(2$f$$ t $+$ B$)$ with $0$ A$$ and $-180$ B$180$

and as a phasor I $=$ A$$ e$^($jB$)$ with $0$ A$$ and $-180$ B$180$

Given Variables: D : $3$ A E$1$ : $1$ ms E$2$ : $-0\mathrm{.}9$ ms

Calculate the following: f$1(1/$s$)$: