The integral symbol, ,   in the heading for this section indicates that it is meant to be read   by students in calculus-based physics. Stu- dents in an   algebra-based physics course should skip these sections. The calculus-related   sections in this book are meant to be usable by students who are   taking calculus concurrently, so at this early point in the physics   course I do not assume you know any calculus yet. This section is   therefore not much more than a quick preview of calculus, to help you   relate what you’re learning in the two courses.  |   
Newton was the  rst person to  gure out the tangent-line de -  |   
nition of velocity for   cases where the x - t graph is nonlinear. Be- fore Newton, nobody   had conceptualized the description of motion in terms of x - t and   v - t graphs. In addition to the graphical techniques discussed   in this chapter, Newton also invented a set of symbolic techniques   called calculus. If you have an equation for x  |   
in terms of t,   calculus allows you, for instance, to    nd an equation for v in terms of t.   In calculus terms, we say that the function v(t) is the derivative of   the function x(t). In other words, the derivative of a function is a new   function that tells how rapidly the original function was changing.   We now use neither Newton’s name for his technique (he called   it “the method of  uxions”) nor his   notation. The more commonly used   notation is due to Newton’s German con- temporary Leibnitz,   whom the English accused of plagiarizing the calculus from Newton.   In the Leibnitz notation, we write  |