Gnuplot is a portable command-line driven graphing utility for Linux, OS/2, MS Windows, OSX, VMS, and many other platforms. It was created to allow scientists and students to visualize mathematical functions and data interactively, but has grown to support many non-interactive uses such as web scripting.
f(x) = a1 + a2*x + a3*x**2 + a4*x**3 + a5*x**4 + a6*x**5 + a7*x**6 + a8*x**7 + a9*x**8 + a10*x**9 + a11*x**10 fit f(x) "bla.dat" using 2:1 via a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11 set title "Polynominal Approximation" set xrange [0:4.8] set xtics 0.4 set xlabel "ADC Voltage" set terminal png set output "polynom.png" plot "bla.dat" using 2:1 title "Simulation", f(x) title "Polynom n. Ordnung" #pause mouse any