William Anthony Granville

“ An automobile course is elliptic in form, the major axis being 6 miles long and running east and west, while the minor axis is 2 miles long. If a car starts north at the extreme east point of the course, in what direction will the car be going
(a) when 2 miles west of the starting point? ”

“ When is defined as an implicit function of by means of an equation in the form
(A) , it was explained in the last section how it might be inconvenient to solve for in terms of ; that is, to find as an explicit function of so that the formulas we have deduced in this chapter may be applied directly. Such, for instance, would be the case for the equation
(B) . We then follow the rule:
Differentiate, regarding as a function of , and put the result equal to zero. [2] That is,
(C) . Let us apply this rule in finding from (B) .
; by (C) ; ; ; Ans. ”