I imagine the clues are hinting towards
The tangent line within the first picture means that we need to calculate the slope of the operate $a = eru$. We are able to take the spinoff of the operate with respect to $e$ to get $da/de = ru$. Rearranging phrases offers us $da = impolite$, i.e., Darude, the artist of the music in query.
I feel the second clue is hinting towards the enduring 5 beat “du du du du du” that the music begins with, with the pause image subsequent to the time signature referring to the musical relaxation between every set of 5 beats.
<OP Edit – The 5 and I are in reference to Morse Code, that are dit-dit-dit-dit-dit and dit-dit, respectively. They’re positioned on a percussion cleff (not a bass or treble) to indicate that the rhythm is what’s vital>
As for the title
Calculus is Latin for “small rock.” So dry calculus might be taken to imply “sand” in addition to the mathematics we have to do for the primary clue