Message Boards Message Boards

7 Replies
0 Total Likes
View groups...
Share this post:

Can anybody post result of provided input to Mathematica?

Posted 11 years ago
Hello to everybody! Can anybody post result of this input to Mathematica?
Reduce[1/4 (-1 + 4 c E^(-(1/2) t1 v1) + E^(t2 v1)) \[Alpha] - ((-1 +
       E^(t2 v1)) \[Psi]11)/(2 v1) >= \[Alpha] && \[Alpha] > 0 &&
  v1 > 1 && t1 > 0 && t2 > 0, c, Reals]
What i see
Solve::nsmet: This system cannot be solved with the methods available to Solve. >>
Is it a bug or i just don't understand something?
7 Replies
Thanks for pointing out the typo, I just corrected it. It seems that Mathematica knows how to handle the equation but the inequality: 
Probably this is a part that needs improvements. 
POSTED BY: Shenghui Yang
So, it is a bug, right? (And it does not depend on whether i use Subscript[]s)
P.S. And thanks for advice to use CoefficientList! But also i should note that your usage seems to be erroneous since coefficients start with power 0. So the coefficient at c is always positive. So, it seems to be a bug.
Also, please note that you may have to sepcify the behavior of the coefficient below to solve for the inequality

You may want to replace it with a symbol first and then specify its domain before you reduce the given inequality because the sign of the coefficient of c matters. 
POSTED BY: Shenghui Yang
I think this expression should work in Mathematica. If I use the simpler notation in the expression, I can rewrite it as
expr = 1/4 (-1 + 4  c  E^(-(1/2) t1 v1) + E^(t2 * v1)) \[Alpha] - ((-1 + E^(t2 *v1)) \[Psi]11)/(2 v1)
This is indeed a simple polynomial in terms of c:
In[93]:= PolynomialQ[expr, c]
Out[93]= True
The coefficients are

Therefore you can either find the solution via:
Or use the coefficients in the list above (the first over the second). 
POSTED BY: Shenghui Yang
Also if you would use code without Subscript but using a simpler notation like t1 or v1, the code would look much more readable here on Community posts.
POSTED BY: Vitaliy Kaurov
Hi there, Solve has to be used for polynomial equations, Reduce for transcendental ones. Nevertheless, neither Reduce nor FindInstance succeeded with this. Possibly you should state also something about 
Subsuperscript[\[Psi], 1, 1]
shouldn´t you?
POSTED BY: Udo Krause
Same answer, sorry.
POSTED BY: Blanca Parra
Reply to this discussion
Community posts can be styled and formatted using the Markdown syntax.
Reply Preview
or Discard

Group Abstract Group Abstract