The calculation of an indefinite integral can be considered as the reverse operation of differentiation.

The calculation of definite integrals is an important part of calculus.

In order to calculate the integral constant, it is necessary to solve the differential equation.

What is the area of this room?

His achievements are very impressive.

He works digging out coal.

He is an expert in petrochemistry.

This beautiful lapis lazuli necklace is my favorite.

She likes collecting gemstones.

He is an expert in chemical analysis.