Understanding Engineering Mathematics

(やまだぃちぅ) #1

9 Techniques of Integration


Most of us find integration difficult – basically because we are always trying to ‘undo’
some differentiation, which might have been difficult in the first place! There are no short
cuts to good integration skills – practice, practice, practice is the only way. Plenty of that
is provided in this chapter. In this case the review test covers a wide range, which reflects
the importance of the material.


Prerequisites
It will be helpful if you know something about:


  • differentiation (Chapter 8



)


  • properties of the elementary functions (Chapters 4, 6)

  • partial fractions (62



)


  • completing the square (66



)

Objectives
In this chapter you will find:


  • definition of integration

  • standard integrals

  • addition of integrals

  • simplifying the integrand

  • linear substitution in integration

  • thedu=f′(x)dxsubstitution

  • integration of rational functions

  • use of trig identities in integration

  • using trig substitutions in integration

  • integration by parts

  • choice of integration methods

  • definite integrals


Motivation
You may need the material of this chapter for:


  • solving differential equations (➤Chapter 15)

  • calculating areas and volumes (➤Chapter 10)

  • calculating mean and RMS values (➤Chapter 10)

  • calculating moments, centroids, etc. (➤Chapter 10)

  • calculating means, standard deviations, and probabilities

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