The Integral is written as "S" and “s” to find the area under the curve.

∫2xdx$$\int 2xdx$$

The 2x is what we want to integrate of a function, it has ∫ as an integral symbol. The dx helps to show us the direction which is on the x-axis and dy on the y-axis.
The integrand or Integral Calculator calculates the function by using integral symbol.

then at the end we put dx to indicate that the slices go in the x-axis direction and in width it’s approach to zero.

And here is how we write the answer:

∫2x+1dx