✔ 最佳答案
gradient of any curve is given by its first derivative i.e. dy/dx.
dy/dx = [(-1)x^2 - 2x(2-x)] / (x^2)^2
= [x^2-4x]/x^4
= [x-4]/x^3
at the x axis, y = 0 , putting this into y = [ 2 - x ] / x^2 , we obtain x=2
put this value into dy/dx
-->dy/dx= [2-4]/(2)^3 = -1/4