Re: Having some trouble with plot and solve

*To*: mathgroup at smc.vnet.net*Subject*: [mg115529] Re: Having some trouble with plot and solve*From*: Alexei Boulbitch <alexei.boulbitch at iee.lu>*Date*: Thu, 13 Jan 2011 03:29:51 -0500 (EST)

Hi, you may go the following way. Copy the code below to the Input cell of your notebook and execute it. Epsilon is the value you are looking for. data = {{0, .005}, {100, .00465}, {200, .00432}, {400, .00374}, {600, \ .00323}, {900, .00260}, {1200, .00209}, {1500, .00168}}; (* Here the data is logarithmed and the new list contains the pairs (t, Log[c]): *) Clear[g]; g[{x_, y_}] := {x, Log[y]}; dataLog = Map[g, data] (* Here we fit the logarithmed data *) ftLog = Fit[dataLog, {1, t}, t] \[Epsilon] = Abs[ftLog[[2, 1]]] (* The following 3 operations are only to visualize the result and get roughly an impression, if the fit we have found indeed fits. *) lstLogPl = ListPlot[dataLog, PlotStyle -> Red, AxesLabel -> {Style["t", 16, Italic], Style["ln(c)", 16, Italic]}]; ftLogPl = Plot[ftLog, {t, 0, 1500}]; Show[{lstLogPl, ftLogPl}] Have fun, Alexei Hi i am new to mathematica, i have tried to combine this simple problem of showing a Reaction speed but i cannot plot the tangent line on a plot, and i don't seem to be able to have my regression in the same notebook data = {{0, .005}, {100, .00465}, {200, .00432}, {400, .00374}, {600, \ .00323}, {900, .00260}, {1200, .00209}, {1500, .00168}}; N2O5 = Exp[Fit[data /. {x_, y_} -> {x, Log[y]}, {1, x}, x]] // Simplify (*not in same notebook as the rest*) f[x_] := 0.00499929 E^(-0.000726892 x) (*this works*) g=B4[x_] := -3.63394*10^-6 E^(-0.000726892 x) (*this works*) Plot[0.00499929 E^(-0.000726892 b), {b, 0, 4000}, PlotRange -> {0, .006}](*this works*) Show[Plot[0.00499929 E^(-0.000726892 x), {x, -1000, 4000}], ListPlot[data, PlotRange -> {0, .006}, PlotStyle -> {Red}]] (*this works*) Manipulate[ Solve[g=B4[x0]*{x - x0} + f[x0] == y], {x0, 0, 1500, 1, Appearance -> "Labeled"}] (*this works*) But i cannot combine it together, not even this small thing Manipulate[ Plot[y /. Solve[g\.b4[x0]*{x - x0} + f[x0] == y], {x0, 0, 1500, 1, Appearance -> "Labeled"}], {x, 0, 4000}, PlotRange -> {0, .006}] Please help me, thanks -- Alexei Boulbitch, Dr. habil. Senior Scientist Material Development IEE S.A. ZAE Weiergewan 11, rue Edmond Reuter L-5326 CONTERN Luxembourg Tel: +352 2454 2566 Fax: +352 2454 3566 Mobile: +49 (0) 151 52 40 66 44 e-mail: alexei.boulbitch at iee.lu www.iee.lu -- This e-mail may contain trade secrets or privileged, undisclosed or otherwise confidential information. If you are not the intended recipient and have received this e-mail in error, you are hereby notified that any review, copying or distribution of it is strictly prohibited. Please inform us immediately and destroy the original transmittal from your system. Thank you for your co-operation.