If f(x) is a differentiable function, the differential of the function corresponding to the increase of the independent variable, h, is the product f'(x) · h. It is denoted by dy.

The differential at a point represents the increase of the y-coordinate of the tangent, which corresponds to an increase in the independent variable, h.


Calculate the increase in the area of a square of 2 when each side is increased by 1mm.

S = x²dS = 2x dx

d(S)= 2·2· 0.001 = 0.004 m²

Did you like the article?

1 Star2 Stars3 Stars4 Stars5 Stars (1 votes, average: 5.00 out of 5)


I am passionate about travelling and currently live and work in Paris. I like to spend my time reading, gardening, running, learning languages and exploring new places.

Did you like
this resource?


Download it in pdf format by simply entering your e-mail!

{{ downloadEmailSaved }}

Your email is not valid