Two pure sine waves have similar amplitude "A" and frequency "f." They are out of phase through 180 degrees. If these two signals are added, the resulting waveform will be:
- Nothing
- A sinewave along with amplitude of 2a and frequency 2f.
- A sinewave along with an amplitude of "a" and out of phase by 90° from both waveforms in reverse directions.
- A sinewave along with an amplitude of a/2 and frequency "f."