The current at resonance in a series RLC circuit is described in the bottom derivation, along with it being plugged into the formula for finding the voltage across the inductor in the circuitw:
I have two questions regarding this derivation.
- Isn't the current at resonance supposed to include the phase shift φ? Why is it left out of the equation? Example: I*sin(ωt+φ)
- When the equation for the current at resonance is plugged into the equation for finding the voltage across the inductor, why is the trigonometric part of the differentiated current equation neglected in the next step?