@Plano tanxente a unha superficie $z=f(x,y)$ nun punto
system:sage


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<H3>Plano tanxente a unha superficie $z=f(x,y)$ nun punto</H3>
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#auto
%hide
var('x,y,z')
@interact
def example(f='sin(x*y)^2', rango_x='(-2, 2)', rango_y='(-2,2)',punto='(1,0)'):
    xmin, xmax = sage_eval(rango_x); ymin, ymax = sage_eval(rango_y);px,py=sage_eval(punto);
    f=f.replace('^','**')
    tg(x,y) = eval(f)
    Pt=tg(px,py)+(x-px)*diff(tg,x)(px,py)+(y-py)*diff(tg,y)(px,py)   
    html('<h2>O plano tanxente é $z=%s$</h2>'%latex(Pt))
    S = plot3d(eval(f), (x, xmin, xmax), (y, ymin, ymax),opacity=0.4)
    T = plot3d(Pt, (x, xmin, xmax), (y, ymin, ymax),color='red')
    show(S+T)
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<html><!--notruncate--><div padding=6 id='div-interact-0'> <table width=800px height=20px bgcolor='#c5c5c5'
                 cellpadding=15><tr><td bgcolor='#f9f9f9' valign=top align=left><table><tr><td align=right><font color="black">f&nbsp;</font></td><td><input type='text' value="sin(x*y)^2" size=80 onchange='interact(0, "_interact_.update(0, \"f\", 1, _interact_.standard_b64decode(\""+encode64(this.value)+"\"), globals());_interact_.recompute(0)")'></input></td></tr>
<tr><td align=right><font color="black">rango_x&nbsp;</font></td><td><input type='text' value="(-2, 2)" size=80 onchange='interact(0, "_interact_.update(0, \"rango_x\", 2, _interact_.standard_b64decode(\""+encode64(this.value)+"\"), globals());_interact_.recompute(0)")'></input></td></tr>
<tr><td align=right><font color="black">rango_y&nbsp;</font></td><td><input type='text' value="(-2,2)" size=80 onchange='interact(0, "_interact_.update(0, \"rango_y\", 3, _interact_.standard_b64decode(\""+encode64(this.value)+"\"), globals());_interact_.recompute(0)")'></input></td></tr>
<tr><td align=right><font color="black">punto&nbsp;</font></td><td><input type='text' value="(1,0)" size=80 onchange='interact(0, "_interact_.update(0, \"punto\", 4, _interact_.standard_b64decode(\""+encode64(this.value)+"\"), globals());_interact_.recompute(0)")'></input></td></tr>
</table><div id='cell-interact-0'><?__SAGE__START>
        <table border=0 bgcolor='#white' width=100% height=100%>
        <tr><td bgcolor=white align=left valign=top><pre><?__SAGE__TEXT></pre></td></tr>
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        </table><?__SAGE__END></div></td>
                 </tr></table></div>
                 </html>
}}}

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