Problem $09\mathrm{.}002-$ DEPENDENT MULTI$-$PART PROBLEM $-$ ASSIGN ALL PARTS

A current source in a linear circuit has $i_S=25cos(At+25)A.$

NOTE: This is a multi$-$part question. Once an answer is submitted, you will be unable to return to this part.

Problem $09\mathrm{.}002.$c $-$ Frequency of a sinusoid

Find the frequency of the current, where $A=23.$

The frequency of the current is $$ Hz$.$