例1求函数y=x3当x=2,△x=0.02时的微分 解∵小 =(x)△x=3x2△x 小y=2=3x2△x 0.24. Ax=0.02 △r=0.02 Economic-mathematics 18-8 Wednesday, February 24, 2021Economic-mathematics 18- 8 Wednesday, February 24, 2021 例1 解 2, 0.02 . 求函数 y = x 3 当 x = x = 时的微分 dy = (x )x 3  3 . 2 = x x 0.02 2 2 0.02 2 3  = =  =  = =  x x x dy x x x = 0.24