From: nma@12000.org   
      
   On 11/22/2016 4:27 PM, clicliclic@freenet.de wrote:   
      
   > Derive 6.10 evaluates INT(SEC(t), t) to LN(TAN((2*t + pi)/4)). Stepwise   
   > evaluation gives:   
   >   
   > INT(SEC(t),t)   
   >   
   > " SEC(z) -> 1/COS(z) "   
   >   
   > INT(1/COS(t),t)   
   >   
   > " INT(1/COS(a*x+b),x) -> LN(COS(a*x+b))/a-LN(1-SIN(a*x+b))/a "   
   >   
   > LN(COS(t))-LN(-SIN(t)+1)   
   >   
   > " one final step "   
   >   
   > LN(TAN((2*t+pi)/4))   
   >   
   > The mechanics of the final step is a mystery to me.   
   >   
   > Martin.   
   >   
      
   I also tried to see how LN(TAN((2*t+pi)/4)) same about, but   
   gave up after few tries. But I just saw this is also given   
   in Schaum's outlines, "mathematical handbook of formulas   
   and tables", second edition, page 65. Here is screen shot of the page   
   fyi.  #16.15 on the page   
      
   http://12000.org/tmp/122116/sec.jpg   
      
   If someone knows how this was derived, it will interesting   
   to know.   
      
   --Nasser   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)