Tikz for f(x)=5x^2-2x and tangent line at 1,3

[karush]

Spoiler: tikz code

\begin{tikzpicture}[xscale=2,yscale=.5]
      \draw[->] (-1,0) -- (4,0) node[right] {$x$};
      \draw[->] (0,-1) -- (0,5) node[above] {$y$};
      \draw[scale=0.5,domain=-1:3.5,smooth,variable=\x,black] plot ({\x},{\x*\x});
  \end{tikzpicture}

ok I am actually trying to plot
$f(x)=5x^2-2x$
with the tangent line going thru $(1,3)$ which is $8\left(x-1\right)+3$

I thot I could just change this from an example but does seem to like it
stack exchange had some samples but they got very complex with other features added

anyway mahalo ahead
why is the preview right justified

 

[I like Serena]

There is a [right] in there.
It's the one big issue TikZ has on this site.
The forum software has its own idea what to do with [right], which is to right align text.

The work-around is to add spaces and make it [ right ].

 

[karush]

ok, more tomorrow Mahalo

 

[karush]

basically got it... maybe some more info on it
I flattened it since it is too tall to show on LinkedIn

\begin{tikzpicture}[xscale=1,yscale=.1]
[help lines/.style={black!50,very thin}]
\draw[-,thin] (-1,0)--(1.5,0) node[below] {$x$};
\draw[-,thin] (0,-1)--(0,6) node[above] {$y$};
\node [below] at (1,0) {$1$};
\draw[very thick,color=black] plot [domain={-1}:{1.5},smooth]
(\x,{5*\x*\x-2*\x)});
\draw[thin,color=red] plot [domain={0}:{1.5},smooth]
(\x,{8*\x-5)});
\end{tikzpicture}

 

[karush]

hi

 

[karush]

want to improve to markup on this MHB posts that I get over a 1000 views
on the few that I have posted already got over 1100 view from LindedIn
start to put the MHB link for those interested in a forum
their are many students on IN from my alma mater APU
I read somewhere that linkedin is going to have an equation wirterView attachment 11842