Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Re: Ploting Tangent Line Date: Fri, 26 Dec 2008 17:28:02 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 13 Message-ID: <gj3472$4ip$1@fred.mathworks.com> References: <gj1ikr$nii$1@fred.mathworks.com> <gj1rjn$mbg$1@fred.mathworks.com> <gj237h$chv$1@fred.mathworks.com> Reply-To: <HIDDEN> NNTP-Posting-Host: webapp-03-blr.mathworks.com Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit X-Trace: fred.mathworks.com 1230312482 4697 172.30.248.38 (26 Dec 2008 17:28:02 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Fri, 26 Dec 2008 17:28:02 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1187260 Xref: news.mathworks.com comp.soft-sys.matlab:508834 "Model Ramachandran" <selvakumar.ram@gmail.com> wrote in message <gj237h$chv$1@fred.mathworks.com>... > ........ > the problem : in my graph I know the maximum value of Y-Axis point . > At which X axis value Y value is maximum (X=Y(MAX)), So I need to draw the tangent line at maximum Y (i.e Y max forparticular X value). > This tangent Line Intersects at some point in X-Axis.I have to find out that value > Stil I am trying A line tangent to your graph at its point of maximum y-value would have to be a horizontal line that would never intersect the x-axis unless it were the x-axis itself. In any case, that way there could never be a unique point of intersection with the x-axis. Stated differently, to have a unique solution to the equation I mentioned, the derivative, f'(x1), must be non-zero, which is incompatible with f(x1) being a point of maximum value of f(x). You must look for something other than the maximum point on your graph in your search for the desired point of tangency. When you say "tangent line" is it possible you mean something other than a line tangent to the graph? Are you possibly talking about the "tangent" function in some sense? That would be an entirely different matter. Roger Stafford