=for timestamp
Di Okt  5 16:11:12 CEST 2004

=head3 9. Hausaufgabe

=head4 Selbstgestellte Aufgabe

M<<
{} \begin{array}{rcl}
{}   f\left(x\right) & = & 2\cdot\mathrm{sgn}\left(x^2 - 4\right) - \left|x+2\right| = \\
{}   & = & \begin{cases}
{}     4 + x  & \text{f"ur } x < -2; \\
{}     0      & \text{f"ur } x = -2; \\
{}     -4 - x & \text{f"ur } -2 < x < 2; \\
{}     -4     & \text{f"ur } x = 2; \\
{}     -x     & \text{f"ur } x > 2;
{}   \end{cases}
{} \end{array}
>>

=helper MyBook::Helper::Gnuplot

f(x) = 2.*sgn(x**2 - 4) - abs(x + 2)

set grid
set xrange [ -4 : 4 ]
set yrange [ -7 : 3 ]
plot "<echo -e '-4 0\\n-2 2\\n-2 0\\n-2 -2\\n2 -6\\n2 -4\\n2 -2\\n4 -4'" \
  t 'f(x)' \
  with l

=hend