<Dl> <Dd> d d R L (R S 2 / R L + 2 R S + R L) = − R S 2 / R L 2 + 1 . (\ displaystyle (\ frac (d) (dR_ (\ mathrm (L)))) \ left (R_ (\ mathrm (S)) ^ (2) / R_ (\ mathrm (L)) + 2R_ (\ mathrm (S)) + R_ (\ mathrm (L)) \ right) = - R_ (\ mathrm (S)) ^ (2) / R_ (\ mathrm (L)) ^ (2) + 1 .) </Dd> </Dl> <Dd> d d R L (R S 2 / R L + 2 R S + R L) = − R S 2 / R L 2 + 1 . (\ displaystyle (\ frac (d) (dR_ (\ mathrm (L)))) \ left (R_ (\ mathrm (S)) ^ (2) / R_ (\ mathrm (L)) + 2R_ (\ mathrm (S)) + R_ (\ mathrm (L)) \ right) = - R_ (\ mathrm (S)) ^ (2) / R_ (\ mathrm (L)) ^ (2) + 1 .) </Dd> <P> For a maximum or minimum, the first derivative is zero, so </P> <Dl> <Dd> R S 2 / R L 2 = 1 (\ displaystyle R_ (\ mathrm (S)) ^ (2) / R_ (\ mathrm (L)) ^ (2) = 1) </Dd> </Dl>

Is maximum power transfer theorem applicable to ac circuits