Sound in Vegas is presented as waves, but I need it to be presented as waves and as a spectrogram at the same time, like in Audacity:
Sound in the form of a spectrogram is needed in Vegas, because work is carried out with many markers that are imported to the timeline in the following format: hours:minutes:seconds:frames. Therefore, other programs will not work for my work
Not a perfect solution but you can render the audio clip into a spectrogram video clip and put that under the audio on the timeline. You should then see preview thumbs of the video under the audio track. They'll be be more discontinuous than the audio waveform but display accurately in the preview area. As you spread out the timeline scale they'll get more accurate in the clip area as you get closer to single-frame preview display.