Step 1 :1. Euler: \(y_{n+1} = y_n + h(y_n - \frac{2 t_n}{y_n})\)
Step 2 :2. Taylor: \(y_{n+1} = y_n + h(y_n - \frac{2 t_n}{y_n}) + \frac{h^2}{2}(2 - \frac{2}{y_n^2})\)
Step 3 :3. Runge Kutta ordre 2: \(k_1 = y_n - \frac{2 t_n}{y_n}\), \(k_2 = (y_n + hk_1) - \frac{2 (t_n + h)}{y_n + hk_1}\), \(y_{n+1} = y_n + \frac{h}{2}(k_1 + k_2)\)
Step 4 :4. Runge Kutta ordre 4: \(k_1 = y_n - \frac{2 t_n}{y_n}\), \(k_2 = (y_n + 0.5hk_1) - \frac{2 (t_n + 0.5h)}{y_n+0.5hk_1}\), \(k_3 = (y_n + 0.5hk_2) - \frac{2 (t_n + 0.5h)}{y_n + 0.5hk_2}\), \(k_4 = (y_n + hk_3) - \frac{2 (t_n + h)}{y_n + hk_3}\), \(y_{n+1} = y_n + \frac{h}{6}(k_1 + 2k_2 + 2k_3 + k_4)\)