what is wrong in this code

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Angad Singh Agarwal
Angad Singh Agarwal am 12 Feb. 2017
Kommentiert: Torsten am 13 Feb. 2017
syms t;
y=(3.7).*(10).^17;
y=3.88*(10).^16.*(t).^(1.5).*exp(-7000./t);
k=solve(y);
  1 Kommentar
Stephen23
Stephen23 am 12 Feb. 2017
@Angad Singh Agarwal: I formatted your code correctly by selecting the code text and then clicking the {} Code button. Next time you can do this yourself.

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Antworten (2)

sjoerd
sjoerd am 12 Feb. 2017
Bearbeitet: sjoerd am 12 Feb. 2017
Althought it is not completely clear to me what your question/problem exactly is, I will give it a try I assumed that you want to solve the following equation for t:
3.7e17 = 3.88e16*(t)^(1.5)*exp(-7000./t)
Please note the use of 'e' for the scientific notations which makes its way shorter. Next to this I removed the dots because no need to solve this element wise (only scalar calculations).
The main problem with your code is that you first assign a value to to 'y' and then overwrite this value with the full equation. So introducing a different variable gives the following.
syms t;
result=3.7e17;
y=3.88e16*(t)^(1.5)*exp(-7000/t);
k=solve(y==result);
And this solves for t, (it will give warning that it is not symbolically solved but a numerical approximation is used).
k = 833 (approximately)
  3 Kommentare
Angad Singh Agarwal
Angad Singh Agarwal am 13 Feb. 2017
Bearbeitet: per isakson am 13 Feb. 2017
showing following error
??? Error using ==> char
Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189
vc = char(v);
Error in ==> solve at 67
[eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4
k=solve(y==result);
??? Error using ==> char
Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189
vc = char(v);
Error in ==> solve at 67
[eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4
k=solve(y==result);
??? Error using ==> char
Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189
vc = char(v);
Error in ==> solve at 67
[eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4
k=solve(y==result);
sjoerd
sjoerd am 13 Feb. 2017
I think you need to give us a little bit more information, which Matlab version do you use? I am using R2015a and it works fine. Furthermore showing a single error stack is also fine ;)

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Torsten
Torsten am 13 Feb. 2017
syms t
result=3.7e17;
y=3.88e16*(t)^(1.5)*exp(-7000/t);
k=solve(y==result,t);
Best wishes
Torsten.
  2 Kommentare
Angad Singh Agarwal
Angad Singh Agarwal am 13 Feb. 2017
??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result,t); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result,t); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result,t); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result,t); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result,t); ??? Error using ==> char Conversion to char from logical is not possible.
Error in ==> solve>getEqns at 189 vc = char(v);
Error in ==> solve at 67 [eqns,vars] = getEqns(varargin{:});
Error in ==> Untitled2 at 4 k=solve(y==result,t);
Torsten
Torsten am 13 Feb. 2017
You seem to use an older MATLAB version.
Take a look into your documentation to see how to use "solve" for your release.
Best wishes
Torsten.

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