calculate-the-estimated-change-in-surface-area-of-a-cone-with-a-slant-height-ll-

Question

Write the differential of the surface area of a cone with a slant height ll, when the slant height changes from ll to l+dll + dl.

Accepted Answer

﻿dA=πr dldA=\pi r\,dldA=πrdl﻿

Answer

dA=πl dldA=\pi l\,dl

Answer

dA=πr ldldA=\pi r\,ldl

Answer

dA=2πr dldA=2\pi r\,dl