A general geometry and calculus : including book I. of the general geometry, treating of loci in a plane; and an elementary course in the differential and integral calculus (1881)
Olney, Edward, 1827-1887 · New York : Sheldon and Co. · leaf 184
Ex. 2. Find the envelope oi y = ax -\ , a being the parameter. Construct a figure illustrating the result. The envelope is y^ = 4m^. Ex. 3. A line of fixed length slides between two fixed lines at rightangles to each other ; required the envelope. Solution.—Let the axes AX and AY be tlie fixedlines… … We have also a^-\-b^ = c^ (2). The most direct method (not the most expeditious) would now be, to find the value of a or 6, from (2), and substitute it in (1), which would then have but a single parameter and its envelope could be found as before. But the following method is less tedious :…
Geometry, Analytic · Calculus
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