.42 



interpreted, for example, as Taylor's tangent value t. The resulting equation 

 is of the type 



nit) = * (0 - Jf U 2 - =1 f * 4 + }l 6 ] [38] 



Here 77 (£) is a given polynomial complying with the condition <f> = const; its 

 tangent value t may be chosen in such a way that the equation 77 is as simple 

 as possible. The function 



|[^ 2 -^ff+'-l**] = * 2 r,(t) [38a] 



has the properties: 



dA. * ) 



2. 4 2 77(0) = 4 2 7?(1 ) = 



3. f4 n(f)df = 

 Jo 



t' is the variable tangent parameter, the resulting t of the Equation [38] 



being obviously t = t' + t . 



Assuming = 2/3, v = 1 - f 2 



!*-: 2 ^.jt.[* -^ + 7*-] 



d£ 



one obtains 



with 



R = ^ t« 2 A + 3t'A + 477? [39] 



§T = ! t ' A 2 +5A 1 = [39a] 



2 11 9 33 55 3 13 15 3 

 A = TTj --^tW + 17T] 



1 'll 3 13 15 



hence 



t' = -f-^- [39b] 



2 



Another isoperimetric problem is given by t = const and <f> variable. 

 Although this problem looks somewhat artificial since there are no technical 

 reasons to keep the tangent of the sectional-area curve rigidly fixed the 



