گرادیان کاهشی

${\displaystyle \mathrm{\nabla }f(x_1,x_2)=\left[\begin{array}{c}-2\times (1-x_1)-400\times (x_2-{x_1}^2)\times x_1\\ 200\times (x_2-{x_1}^2)\end{array}\right]}$

${\displaystyle \left[\begin{array}{c}{x}_1^{n+1}\\ x_2^{n+1}\end{array}\right]=\left[\begin{array}{c}{x}_1^n\\ x_2^n\end{array}\right]-0.1\times \left[\begin{array}{c}-2\times (1-x_1^n)-400\times (x_2^n-{x_1^n}^2)\times x_1^n\\ 200\times (x_2^n-{x_1^n}^2)\end{array}\right]}$