Re: Manipulate help
- To: mathgroup at smc.vnet.net
- Subject: [mg128592] Re: Manipulate help
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Thu, 8 Nov 2012 02:08:46 -0500 (EST)
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- Reply-to: nma at 12000.org
On 11/6/2012 11:58 PM, 07.350z wrote: > Create a Manipulate demonstration that draws the tangent line to a curve at the point >specified by a continuous control. For the curve, the user should be able to >choose between the graphs of the following functions. Make sure your demonstration >shows the curve, the point, and the tangent line at that point. The functions are 7cos(x), > x^2/10, 2ln(1+x^2) > > Show[Manipulate[ > Plot[y, {x, -10, 10}, > PlotRange -> {-10, 10}], {y, {7 Cos[x], x^2/10, 2*Log[1 + x^2]}}], > Do[Module[{slopeM, tangentLine, x}, > slopeM = D[{7 Cos[x], x^2/10, 2*Log[1 + x^2]}, x] /. x -> t; > tangentLine = slopeM*x - t; > Return[ > Plot[{{7 Cos[x], x^2/10, 2*Log[1 + x^2]}, tangentLine}, {t, -5, > 5}]]], {x, -10, 10}]] > > I know the first part of code is right, but I'm having trouble adding the tangent line. >Any help would be great thanks! > may be ------------------------------------------- Manipulate[ Module[{lineEquation, pt = {at, y /. x -> at}}, lineEquation = getSlope[at, y, x]; Plot[{y, lineEquation }, {x, -10, 10}, PlotRange -> {-10, 10}, Epilog -> {Red, PointSize[.02], Point[pt]}] ], {y, {7 Cos[x], x^2/10, 2*Log[1 + x^2]}}, {{at, 0, "x"}, -10, 10, 1, Appearance -> "Labeled"}, TrackedSymbols :> {y, at}, Initialization :> ( getSlope[at_, y_, var_] := Module[{slope, h, intercept}, h = y /. var -> at; slope = D[y, var] /. var -> at; intercept = h - at*slope; slope*var + intercept ] ) ] ---------------------------------- --Nasser