RLC voltage at resonance
At resonance, the final voltage on the resistor is precisely what the input sinewave amplitude is. This is because inductive and capacitive reactances totally cancel to zero in an AC analysis.

This then tells you the current flowing through all series components so, use ohms law (for impedances) to calculate the voltage on L and C individually. At resonance they will be the same amplitude and, if their individual reactances are greater than the resistor, you will see that the voltages are larger than the incoming sinewave.

In an off-resonance scenario you calculate the net impedance of the capacitor and inductor (zero at resonance as previously mentioned) and use Pythagoras to determine the voltage across the resistor then proceed as above.