From: nma@12000.org   
      
   On 8/1/2016 11:19 AM, clicliclic@freenet.de wrote:   
   >   
   > For the record: Derive 6.10 cannot solve this differential equation.   
   > Evaluating   
   >   
   >   DSOLVE1_GEN(-y^2 - y*SIN(2*x) - COS(2*x), 1, x, y, c)   
   >   
   > immediately produces the string "inapplicable", and there seems to be   
   > no specialized procedure that could succeed here.   
   >   
   > Plugging your original   
   >   
   >   y := TAN(x)   
   >   + EXP(-COS(x)^2)/(COS(x)^2*(INT(EXP(-COS(x)^2)/COS(x)^2, x) + c))   
   >   
   > into   
   >   
   >   DIF(y, x) - y^2 - y*SIN(2*x) - COS(2*x) = 0   
   >   
   > shows that solution to be wrong, whereas the amended   
   >   
   > y := TAN(x)   
   >   - EXP(-COS(x)^2)/(COS(x)^2*(INT(EXP(-COS(x)^2)/COS(x)^2, x) + c))   
   >   
   > is found to satisfy the equation, reducing it to 0 = 0.   
   >   
   > Martin.   
   >   
      
   Thanks for trying. I think Maple is the most powerful in solving   
   differential equations of all CAS systems. It is also very fast!   
      
   I always wondered why Maple is so good in solving differential   
   equations (vs. say integration for example, where I think Mathematica is   
   stronger there). I would guess Maplesoft happens to have more   
   differential equations experts working there? But I think there is   
   more to it, may be due to how it all started long time ago.   
      
   It Would be interesting to know the history behind this, i.e. why   
   Maple is _relatively_ more advanced in this specific area (and in   
   Physics also, see Physics package) than in some other areas.   
      
   If WRI and Maplesoft would agree to merge into one company, then we   
   will have a CAS that is very strong in both differentiation   
   and integration :)   
      
   --Nasser   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)