(b) (10 分) Find the derivative of f(x,y,z) = x³ - xy² - z at point P₀ (1,1,0) in the direction of the vector v = 2i - 3j + 6k.

1. (10 分) Use Newton's method to find the x-coordinate of the point where the curve y = x² - 2x crosses the horizontal line y = 1. Specifically apply Newton's method with the starting value x0 = 1 to get the first approximation x₁ = ? and then the second approximation x₂ = ? and omit all the other approximations xₙ, n ＞ 2.