x0 = [1 1 1 1 1 1]';
x = newton('kalkvattenfunk',x0,1e-15)

PH = 4:0.5:7;
c = [0.00844335466886 0.00843698972035 0.00843497694656 0.00843434045159 0.00843413917420 0.00843407552471 0.00843405539697];
pH = 4:0.1:7;
C = spline(PH,c,pH);

plot(pH,C,PH,c,'+')
xlabel('pH')
ylabel('[Ca^2^+]  (M)')
grid
