Getting Error: Warning: Unable to find explicit solution.
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Trying to solve for ignition temperature of different materials using equation attached. This is my code:
%G=30,000 W/m^2
%T0=298K
%E=.9
%h= 15 W/m^2/K
%%PMMA
%K*rho*c=10,000,000
%tp=653K
syms t_ign;
eqn = 298+((.9*30000)/15)*(1-exp(225*t_ign/10000000))*erfc(((225*t_ign)/10000000)^(1/2))==653 ;
sol1 = solve(eqn,t_ign);
Anyone know what is wrong??
采纳的回答
madhan ravi
2018-10-30
0 个投票
There is nothing wrong in your code but Matlab is not able to solve the above equation , tried it in Wolfram wasn't able to solve either
4 个评论
Ella Meredith
2018-10-30
madhan ravi
2018-10-30
I think it’s pretty hard to get through because there’s erfi constant in the equation
Walter Roberson
2018-10-30
As a general rule: if you are using solve() with an expression that includes floating point numbers then you are making a mistake. solve() is for finding exact closed form solutions if possible, but any time you have a floating point constant, that is an indication that your inputs are not exact and therefore it is meaningless to get an exact solution.
If you are looking for approximate solutions then vpasolve.
madhan ravi
2018-11-1
Thank you sir Walter for briefing the issue much appreciated
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