1. Because the relationship between the X axis and the Y axis can be strictly guaranteed in the experiment, Li Sharu's graph has been rotating, and when the frequency is close to the integer multiple, the rotation speed is slow;

2.0. 1ms can display 5 waveforms, and the next 50us can only display 2.5 waveforms, so it should be 0.1ms/div;

3, low;

It is still a sine wave.