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082-Engineering-Mathematics-Anthony-Croft-Robert-Davison-Martin-Hargreaves-James-Flint-Edisi-5-2017

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26 Vectorcalculus

Contents 26.1 Introduction 849

26.2 Partialdifferentiationofvectors 849

26.3 Thegradientofascalarfield 851

26.4 Thedivergenceofavectorfield 856

26.5 Thecurlofavectorfield 859

26.6 Combiningtheoperatorsgrad,divandcurl 861

26.7 Vectorcalculusandelectromagnetism 864

Reviewexercises26 865

26.1 INTRODUCTION

This chapter draws together several threads from previous chapters. It builds upon differential

and integral calculus, functions of several variables and the study of vectors.

Thesetopicstogetherformabranchofengineeringmathematicsknownasvectorcalculus.

Vector calculus is used to model a vast range of engineering phenomena including

electrostaticcharges,electromagneticfields,airflowaroundaircraft,carsandothersolid

objects,fluidflowaroundshipsandheatflowinnuclearreactors.Thechapterstartsby

explainingwhatismeantbytheoperatorsgrad,divandcurl.Theseareusedtocarryout

various differentiation operations on the fields.

26.2 PARTIALDIFFERENTIATIONOFVECTORS

Consider the vector field v = v x

i + v y

j + v z

k, where each component v x

,v y

and v z

is a

function ofx,y andz. We can partiallydifferentiate the vector w.r.t.xas follows:

∂v

∂x = ∂v x

∂x i + ∂v y

∂x j + ∂v z

∂x k

This isanew vector with a magnitude and direction different fromthose ofv.

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