Try something like this —
yfcn = @(b,x) b(1).*sqrt(x) + b(2);
x = 0:0.5:10;
y = rand(size(x));
[B,fval] = fminsearch(@(b) norm(y-yfcn(b,x)), rand(2,1))
xv = linspace(min(x), max(x));
yv = yfcn(B,xv);
figure
plot(x, y, '.')
hold on
plot(xv, yv, '-r')
hold off
grid
xlabel('X')
ylabel('Y')
title(sprintf('$y(x) = %.3f \\cdot \\sqrt{x} + %.3f$', B), 'Interpreter','latex')
NOTE — Using ‘sqrt(x)’ is computationally more efficient than ‘x.^0.5’.
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