Integration

Why do we need to study Integration?

by M. Bourne

petronas towers
The Petronas Towers
of Kuala Lumpur

Often we know the relationship involving the rate of change of two variables, but we may need to know the direct relationship between the two variables. For example, we may know the velocity of an object at a particular time, but we may want to know the position of the object at that time.

To find this direct relationship, we need to use the process which is opposite to differentiation. This is called integration (or antidifferentiation).

The processes of integration are used in many applications.

The Petronas Towers in Kuala Lumpur experience high forces due to winds. Integration was used to design the building for strength.

sydney opera house
Sydney Opera House

The Sydney Opera House is a very unusual design based on slices out of a ball. Many differential equations (one type of integration) were solved in the design of this building.

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winecask
Wine cask

Historically, one of the first uses of integration was in finding the volumes of wine-casks (which have a curved surface).

Other uses of integration include finding areas under curved surfaces, centres of mass, displacement and velocity, fluid flow, modelling the behaviour of objects under stress, etc.

We begin with a discussion of the differential, because it involves some of the concepts and notation used in the study of integration. The Differential »