The lyric follows a function through a small change in x, a corresponding change in y, and the limiting quotient. This is the complete nine-line first-page text. Page two repeats the words with screen-caption equations; those captions are not extra lyrics. The sheet credits the musical setting to There'll Be Some Changes Made by W. Benton Overstreet and separately identifies original lyricist Billy Higgins on page two. Only Lehrer's new words are displayed.
You take a function of x and you call it y
Take any x-nought that you care to try
You make a little change and call it delta x
The corresponding change in y is what you find nex'
And then you take the quotient and now carefully
Send delta x to zero, and I think you'll see
That what the limit gives us, if our work all checks,
Is what we call dy/dx,
It's just dy/dx.