Formula:
$$f(x) = \sum_{i=1}^{11}\left(a_i -
\frac{x_1(b_i^2 + b_i x_2)}{b_i^2 + b_i x_3 + x_4}\right)^2$$
where \(a_i\) and \(b_i\) are predefined constants from experimental data.
Global minimum: \(f(0.1928, 0.1908, 0.1231, 0.1358) \approx 0.0003075\)
Characteristics:
This function is derived from a curve-fitting problem and has several
local minima near the global minimum.