diff --git a/p4/data/mesura5_deriva.dat b/p4/data/mesura5_deriva.dat
new file mode 100644
index 0000000..f70f422
--- /dev/null
+++ b/p4/data/mesura5_deriva.dat
@@ -0,0 +1,187 @@
+70.08	1.996E+00
+71.08	1.979E+00
+72.08	1.962E+00
+73.08	1.945E+00
+74.08	1.929E+00
+75.08	1.913E+00
+76.08	1.898E+00
+77.08	1.883E+00
+78.08	1.868E+00
+79.08	1.854E+00
+80.08	1.840E+00
+81.08	1.826E+00
+82.08	1.813E+00
+83.08	1.800E+00
+84.08	1.788E+00
+85.08	1.775E+00
+86.08	1.763E+00
+87.08	1.752E+00
+88.08	1.740E+00
+89.08	1.729E+00
+90.08	1.717E+00
+91.08	1.707E+00
+92.08	1.696E+00
+93.08	1.686E+00
+94.08	1.676E+00
+95.08	1.667E+00
+96.08	1.657E+00
+97.08	1.648E+00
+98.08	1.639E+00
+99.08	1.630E+00
+100.08	1.621E+00
+101.08	1.613E+00
+102.08	1.604E+00
+103.08	1.596E+00
+104.08	1.588E+00
+105.08	1.580E+00
+106.08	1.573E+00
+107.08	1.565E+00
+108.08	1.558E+00
+109.08	1.551E+00
+110.08	1.544E+00
+111.08	1.537E+00
+112.08	1.531E+00
+113.08	1.524E+00
+114.08	1.518E+00
+115.08	1.512E+00
+116.08	1.505E+00
+117.08	1.500E+00
+118.08	1.494E+00
+119.08	1.488E+00
+120.08	1.482E+00
+121.08	1.477E+00
+122.08	1.471E+00
+123.08	1.466E+00
+124.08	1.461E+00
+125.08	1.456E+00
+126.08	1.451E+00
+127.08	1.446E+00
+128.08	1.442E+00
+504.08	3.354E-01
+505.08	3.311E-01
+506.08	3.263E-01
+507.08	3.219E-01
+508.08	3.176E-01
+509.08	3.133E-01
+510.08	3.089E-01
+511.08	3.046E-01
+512.08	3.001E-01
+513.08	2.961E-01
+514.08	2.918E-01
+515.08	2.878E-01
+516.08	2.834E-01
+517.08	2.796E-01
+518.08	2.753E-01
+519.08	2.715E-01
+520.08	2.678E-01
+521.08	2.636E-01
+522.08	2.599E-01
+523.08	2.562E-01
+524.08	2.522E-01
+525.08	2.485E-01
+526.08	2.447E-01
+527.08	2.414E-01
+528.08	2.374E-01
+529.08	2.337E-01
+530.08	2.304E-01
+531.08	2.268E-01
+532.08	2.231E-01
+533.08	2.196E-01
+534.08	2.161E-01
+535.08	2.128E-01
+536.08	2.094E-01
+537.08	2.060E-01
+538.08	2.025E-01
+539.08	1.992E-01
+540.08	1.959E-01
+541.08	1.929E-01
+542.08	1.894E-01
+543.08	1.857E-01
+544.08	1.829E-01
+545.08	1.797E-01
+546.08	1.766E-01
+547.08	1.733E-01
+548.08	1.704E-01
+549.08	1.673E-01
+550.08	1.640E-01
+551.08	1.610E-01
+552.08	1.577E-01
+553.08	1.553E-01
+554.08	1.520E-01
+555.08	1.489E-01
+556.08	1.455E-01
+557.08	1.430E-01
+558.08	1.398E-01
+559.08	1.371E-01
+560.08	1.343E-01
+561.08	1.314E-01
+562.08	1.286E-01
+563.08	1.255E-01
+564.08	1.227E-01
+565.08	1.199E-01
+566.08	1.174E-01
+567.08	1.144E-01
+568.08	1.114E-01
+569.08	1.089E-01
+570.08	1.064E-01
+571.08	1.032E-01
+572.08	1.005E-01
+573.08	9.807E-02
+574.08	9.554E-02
+575.08	9.218E-02
+576.08	8.978E-02
+577.08	8.739E-02
+578.08	8.484E-02
+579.08	8.204E-02
+580.08	7.952E-02
+581.08	7.714E-02
+582.08	7.424E-02
+583.08	7.174E-02
+584.08	6.922E-02
+585.08	6.657E-02
+586.08	6.431E-02
+587.08	6.151E-02
+588.08	5.910E-02
+589.08	5.647E-02
+590.08	5.435E-02
+591.08	5.184E-02
+592.08	4.934E-02
+593.08	4.706E-02
+594.08	4.401E-02
+595.08	4.177E-02
+596.08	3.971E-02
+597.08	3.706E-02
+598.08	3.470E-02
+599.08	3.210E-02
+600.08	2.973E-02
+601.08	2.742E-02
+602.08	2.521E-02
+603.08	2.284E-02
+604.08	2.042E-02
+605.08	1.800E-02
+606.08	1.561E-02
+607.08	1.326E-02
+608.08	1.120E-02
+609.08	8.891E-03
+610.08	6.432E-03
+611.08	4.267E-03
+612.08	2.039E-03
+613.08	-1.470E-04
+614.08	-2.459E-03
+615.08	-4.729E-03
+616.08	-6.905E-03
+617.08	-9.007E-03
+618.08	-1.153E-02
+619.08	-1.359E-02
+620.08	-1.582E-02
+621.08	-1.796E-02
+622.08	-2.038E-02
+623.08	-2.239E-02
+624.08	-2.436E-02
+625.08	-2.682E-02
+626.08	-2.913E-02
+627.08	-3.111E-02
+628.08	-3.323E-02
+629.08	-3.540E-02
+630.08	-3.737E-02
+631.08	-3.980E-02