150cos(120πt) = 60
cos(120πt) = 0.4
since cos(1.15928) = 0.4,
120πt = 1.15928 or 2π-1.15928
now finish it off
3. The voltage, V, in volts, applied to an electric circuit can be modelled by the equation V=150cos(120πt) where t is time, in seconds. Determine when the voltage is 60V for the duration of one cycle. (Always consider multiple solutions)
1 answer