MaplePrimes - Questions and Posts tagged with fsolve
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en-us2017 Maplesoft, A Division of Waterloo Maple Inc.Maplesoft Document SystemMon, 27 Mar 2017 18:20:39 GMTMon, 27 Mar 2017 18:20:39 GMTThe most recent questions and posts on MaplePrimes tagged with fsolvehttp://www.mapleprimes.com/images/mapleprimeswhite.jpgMaplePrimes - Questions and Posts tagged with fsolve
http://www.mapleprimes.com/tags/fsolve
plot of system of equations
http://www.mapleprimes.com/questions/221497-Plot-Of-System-Of-Equations?ref=Feed:MaplePrimes:Tagged With fsolve
<p>Hi</p>
<p> </p>
<p>I have a system of equations (4) which I would like to plot in regards to a fifth variable. Is there a good way to do this. Some of the solutions would end up as negative values, which is not an option I am interested in having.</p>
<p> </p>
<p>C__A is my variable, and the other variables I would like to solve are tau,C__B,C__C,C__D. Im specifically interested in tau with regards to C__A. I hope this makes sense :)</p>
<p>regards</p>
<p> </p>
<p>C__A := .75;<br>
0.75</p>
<p><br>
a := tau = (C__A0-C__A)/(-r__A);<br>
0.75 <br>
tau = - ------------------------------------------------<br>
2 <br>
-0.00900 C__B + 0.03500000000 C__C - 0.075 C__C<br>
b := tau = (C__B0-C__B)/(-r__B);<br>
2 - C__B <br>
tau = - -----------------------------------<br>
2<br>
-0.00900 C__B + 0.03500000000 C__C <br>
c := tau = (C__C0-C__C)/(-r__C);<br>
C__C <br>
tau = ---------------------------------------<br>
2 <br>
0.01800 C__B - 0.070 C__C - 0.075 C__C<br>
d := tau = (C__D0-C__D)/(-r__D);<br>
13.33333333 C__D<br>
tau = ----------------<br>
C__C <br>
sol := fsolve([a, b, c, d], {C__B = 1, C__C = .2, C__D = .2, tau = 50});</p>
<p>{C__B = 1.673672109, C__C = 0.2289836744, C__D = 0.4236721086, </p>
<p> tau = 24.66971264}</p>
<p>Hi</p>
<p> </p>
<p>I have a system of equations (4) which I would like to plot in regards to a fifth variable. Is there a good way to do this. Some of the solutions would end up as negative values, which is not an option I am interested in having.</p>
<p> </p>
<p>C__A is my variable, and the other variables I would like to solve are tau,C__B,C__C,C__D. Im specifically interested in tau with regards to C__A. I hope this makes sense :)</p>
<p>regards</p>
<p> </p>
<p>C__A := .75;<br />
0.75</p>
<p><br />
a := tau = (C__A0-C__A)/(-r__A);<br />
0.75 <br />
tau = - ------------------------------------------------<br />
2 <br />
-0.00900 C__B + 0.03500000000 C__C - 0.075 C__C<br />
b := tau = (C__B0-C__B)/(-r__B);<br />
2 - C__B <br />
tau = - -----------------------------------<br />
2<br />
-0.00900 C__B + 0.03500000000 C__C <br />
c := tau = (C__C0-C__C)/(-r__C);<br />
C__C <br />
tau = ---------------------------------------<br />
2 <br />
0.01800 C__B - 0.070 C__C - 0.075 C__C<br />
d := tau = (C__D0-C__D)/(-r__D);<br />
13.33333333 C__D<br />
tau = ----------------<br />
C__C <br />
sol := fsolve([a, b, c, d], {C__B = 1, C__C = .2, C__D = .2, tau = 50});</p>
<p>{C__B = 1.673672109, C__C = 0.2289836744, C__D = 0.4236721086, </p>
<p> tau = 24.66971264}</p>
221497Mon, 20 Mar 2017 13:51:05 Zbogus5331bogus5331solve with a variable or fsolve without variable
http://www.mapleprimes.com/questions/221436-Solve-With-A-Variable-Or-Fsolve-Without-Variable?ref=Feed:MaplePrimes:Tagged With fsolve
<p> </p>
<p>I've encountered a very strange issue with Maple.</p>
<p>The result returns differently with solve and fsolve after/before a variable is given a certain value. See attachment.</p>
<p>The result comes from solve (with variable epsilon) returns value of the same variable with imaginary part while the fsolve returns the correct answer.</p>
<p>Now how can I achieve the same result as fsolve via solve?</p>
<p>Thanks!</p>
<p><a href="/view.aspx?sf=221436_question/Maple_Question_Solve_Fsolve.mw">Maple_Question_Solve_Fsolve.mw</a></p>
<p><a href="/view.aspx?sf=221436_question/Maple_Question_Solve_Fsolve.pdf">Maple_Question_Solve_Fsolve.pdf</a> (exported PDF from Maple)</p>
<p> </p>
<p>I've encountered a very strange issue with Maple.</p>
<p>The result returns differently with solve and fsolve after/before a variable is given a certain value. See attachment.</p>
<p>The result comes from solve (with variable epsilon) returns value of the same variable with imaginary part while the fsolve returns the correct answer.</p>
<p>Now how can I achieve the same result as fsolve via solve?</p>
<p>Thanks!</p>
<p><a href="/view.aspx?sf=221436_question/Maple_Question_Solve_Fsolve.mw">Maple_Question_Solve_Fsolve.mw</a></p>
<p><a href="/view.aspx?sf=221436_question/Maple_Question_Solve_Fsolve.pdf">Maple_Question_Solve_Fsolve.pdf</a> (exported PDF from Maple)</p>
221436Sun, 12 Mar 2017 19:07:06 Zdellairdellairtrouble using fsolve. Different solver needed?
http://www.mapleprimes.com/questions/221378-Trouble-Using-Fsolve-Different-Solver-Needed?ref=Feed:MaplePrimes:Tagged With fsolve
<p>I have trouble solving this equation</p>
<p> </p>
<p>fsolve(5000 = int(1/(0.1060444429e-1-0.2120888857e-1*X+0.1033933318e-1*X^2), X = 0 .. x), x)</p>
<p>It has a few points where the solution will go towards infinite, but that is not something that is an issue normally. I have no problems what so ever to solve this using my trusty TI-89, so Im wondering what needs to be done to actually solve this. I have tried giving an initial guess, and I have tried using solve, but it doesnt seem to do the trick.</p>
<p> </p>
<p>Regards</p>
<p> </p>
<p>I have trouble solving this equation</p>
<p> </p>
<p>fsolve(5000 = int(1/(0.1060444429e-1-0.2120888857e-1*X+0.1033933318e-1*X^2), X = 0 .. x), x)</p>
<p>It has a few points where the solution will go towards infinite, but that is not something that is an issue normally. I have no problems what so ever to solve this using my trusty TI-89, so Im wondering what needs to be done to actually solve this. I have tried giving an initial guess, and I have tried using solve, but it doesnt seem to do the trick.</p>
<p> </p>
<p>Regards</p>
<p> </p>
221378Mon, 06 Mar 2017 11:55:13 Zbogus5331bogus5331Coordinates of a point
http://www.mapleprimes.com/questions/221309-Coordinates-Of-A-Point?ref=Feed:MaplePrimes:Tagged With fsolve
<p>I've made a system of two equations:</p>
<p>eq1:= x^2+y^2=0.314</p>
<p>eq2:= y=0.05180967688x</p>
<p>The first is a circle while the second is a line. I use the command fsolve in order to get the intersection and i get:</p>
<p>{x=0.5596,y=0.02899}</p>
<p>I need to use these results as the coordinates of a pointplot, how can i do it? Is there a way to isolate x and y?</p>
<p>Thanks</p>
<p>I've made a system of two equations:</p>
<p>eq1:= x^2+y^2=0.314</p>
<p>eq2:= y=0.05180967688x</p>
<p>The first is a circle while the second is a line. I use the command fsolve in order to get the intersection and i get:</p>
<p>{x=0.5596,y=0.02899}</p>
<p>I need to use these results as the coordinates of a pointplot, how can i do it? Is there a way to isolate x and y?</p>
<p>Thanks</p>
221309Mon, 27 Feb 2017 14:51:54 Zmattyred99mattyred99fsolve range problem
http://www.mapleprimes.com/questions/221168-Fsolve-Range-Problem?ref=Feed:MaplePrimes:Tagged With fsolve
<p>Hello everyone,</p>
<p>I have 5 equations (fa,fb,fc,fk,fv) and 5 variables (V0,A0,A1,A2,k1) and I want to solve them <strong>numerically</strong>. Problem is my inability to set properly intervals and starting values. </p>
<p>Here is my command: <strong><em>fsolve({fa,fb,fc,fk,fv},{V0,A0,A1,A2,k1});</em></strong></p>
<p>If I run it just like this, I get some values, lets say V0=0.00045 etc.But when I set range for V0 like this:</p>
<p><strong><em>fsolve({fa,fb,fc,fk,fv},{V0=0.0004..0.0005,A0,A1,A2,k1});</em></strong></p>
<p>I get this:</p>
<p><span style="color:#FF0000;">Error, (in fsolve) fsolve cannot solve on V0 = 0.4e-3 .. 0.5e-3</span></p>
<p>I used interval 0.0004..0.0005 only to prove that there must be the wrong syntax, because obviously 0.0004<0.00045<0.0005. In reality i need interval 0.0001..0.0002 and it is also necessary.to set some initial values (A0=0.0023) but first I need to solve my problem with syntax.</p>
<p>Any advice ?</p>
<p>Hello everyone,</p>
<p>I have 5 equations (fa,fb,fc,fk,fv) and 5 variables (V0,A0,A1,A2,k1) and I want to solve them <strong>numerically</strong>. Problem is my inability to set properly intervals and starting values. </p>
<p>Here is my command: <strong><em>fsolve({fa,fb,fc,fk,fv},{V0,A0,A1,A2,k1});</em></strong></p>
<p>If I run it just like this, I get some values, lets say V0=0.00045 etc.But when I set range for V0 like this:</p>
<p><strong><em>fsolve({fa,fb,fc,fk,fv},{V0=0.0004..0.0005,A0,A1,A2,k1});</em></strong></p>
<p>I get this:</p>
<p><span style="color:#FF0000;">Error, (in fsolve) fsolve cannot solve on V0 = 0.4e-3 .. 0.5e-3</span></p>
<p>I used interval 0.0004..0.0005 only to prove that there must be the wrong syntax, because obviously 0.0004<0.00045<0.0005. In reality i need interval 0.0001..0.0002 and it is also necessary.to set some initial values (A0=0.0023) but first I need to solve my problem with syntax.</p>
<p>Any advice ?</p>
221168Mon, 13 Feb 2017 14:36:07 Zpizza guypizza guyStrange bug in fsolve with Digits
http://www.mapleprimes.com/questions/221085-Strange-Bug-In-Fsolve-With-Digits?ref=Feed:MaplePrimes:Tagged With fsolve
<p>It is well known that <strong>fsolve</strong> usually increases (internally) <strong>Digits</strong> in order to obtain the desired accuracy.</p>
<p>But in the following example, it seems that <strong>fsolve </strong><span style="color:#0000FF;">highly exaggerates</span> :-) </p>
<pre class="prettyprint">
restart;
N:=40:
Digits:=100:
F:=expand(mul(x-k,k=1..N)):
f:=evalf(F):
S:=[fsolve(f,complex)];
</pre>
<p><span style="color:#FF0000;">Error, (in fsolve) Digits cannot exceed 38654705646</span></p>
<p><br>
Note that the bug does not appear if e.g.<strong> F:=expand(mul(x-k-I, k=1..N)):</strong></p>
<p> </p>
<p> </p>
<p>It is well known that <strong>fsolve</strong> usually increases (internally) <strong>Digits</strong> in order to obtain the desired accuracy.</p>
<p>But in the following example, it seems that <strong>fsolve </strong><span style="color:#0000FF;">highly exaggerates</span> :-) </p>
<pre class="prettyprint">
restart;
N:=40:
Digits:=100:
F:=expand(mul(x-k,k=1..N)):
f:=evalf(F):
S:=[fsolve(f,complex)];
</pre>
<p><span style="color:#FF0000;">Error, (in fsolve) Digits cannot exceed 38654705646</span></p>
<p><br>
Note that the bug does not appear if e.g.<strong> F:=expand(mul(x-k-I, k=1..N)):</strong></p>
<p> </p>
<p> </p>
221085Mon, 06 Feb 2017 12:13:52 Zvvvv