MATLAB for Engineers 5th Edition - Complete Solution Manual & Homework Answers

MatlabVforVEngineers,V5thVEdition
ChapterV2VHomeworkVSolutions

clear,clc,VformatVshortg



YouVcanVeitherVsolveVtheseVproblemsVinVtheVcommandVwindow,VusingVMATLAB®VasVanVelectronicV
calculator,VorVyouVcanVcreateVanVM-
fileVofVtheVsolutions.VIfVyouVareVsolvingVtheseVproblemsVasVaVhomeworkVassignmentVorVifVyouVwant
VtoVkeepVaVrecordVofVyourVwork,VtheVbestVstrategyVisVtoVuseVanVM-
file,VdividedVintoVcellsVwithVtheVcellVdividerV%%.

ProblemV2.1
PredictVtheVoutcomeVofVtheVfollowingVMATLAB®Vcalculations.VCheckVyourVresultsVbyVenteringVtheVc
alculationsVintoVtheVcommandVwindow.

1V+V3/4


ansV= 1.75

5*6*4/2


ansV= 60

5/2*6*4


ansV= 60

5^2*3


ansV= 75

5^(2*3)


ansV= 15625

1V+V3V+ 5/5 +V3V+V1

ansV= 9

(1V+V3V+V5)/(5V+V3V+V1)


ansV= 1



UsingVVariablesVPr

oblemV2.2
IdentifyVwhichVnameVinVeachVofVtheVfollowingVpairsVisVaVlegitimateVMATLAB®VvariableVname.VTestV
yourVanswersVbyVusingVisvarname—forVexample,
1

,isvarnameVfred

Remember,VisvarnameVreturnsVaV1VifVtheVnameVisVvalidVandVaV0VifVitVisVnot.VAlthoughVitVisVp
ossibleVtoVreassignVaVfunctionVnameVasVaVvariableVname,VdoingVsoVisVnotVaVgoodVidea.VUseV
whichVtoVcheckVwhetherVtheVprecedingVnamesVareVfunctionVnames—forVexample,

whichVsin

InVwhatVcaseVwouldVMATLAB®tellVyouVthatVsinVisVaVvariableVname,VnotVaVfunctionVna

me?VTheVlegitimateVMatlabVnamesVare:VfredVbook_1VSecond_PlaceVNo_1Vvel_5Vtan

isvarnameVfred


ansV= 1

isvarnameVbook_1


ansV= 1

isvarnameVSecond_Place


ansV= 1

isvarnameVNo_1


ansV= 1

isvarnameVvel_5


ansV= 1

isvarnameVtan %althoughVtanVisVaVfunctionVnameVitVcanVbeVusedVasVaVvariableVname


ansV= 1

isvarnameVfred!V %!VisVnotVanVallowedVcharacter


ansV= 0

isvarnameVbook-1V %V-VisVnotVanVallowedVcharacter


ansV= 0

isvarnameV2ndplaceV %variableVnamesVmustVstartVwithVaVletter


ansV= 0

isvarnameV#1V %#VisVnotVanVallowedVcharacter


ansV= 0

isvarnameVvel.5V %V.VisVnotVanVallowedVcharacter


ansV= 0
2

, isvarnameVwhileV %whileVisVaVreservedVname

ansV= 0


whichVtanV %VtanVisVaVfunctionVname


built-inV(C:\ProgramVFiles\MATLAB\R2016b\toolbox\matlab\elfun\@double\tan)V %VdoubleVmethod

whichVwhileV %whileVisValsoVaVfunctionVname,VbutVisVreserved


built-inV(C:\ProgramVFiles\MATLAB\R2016b\toolbox\matlab\lang\while)


%YouVcanVreassignVaVfunctionVnameVasVaVvariableVname
%ForVexampleVs
in=3


sinV= 3

%TheVwhichVfunctionVnowVtellsVusVsinVisVaVvariableVwhichV
sin


sinVisVaVvariable.

%VUseVtheVclearVfunctionVtoVreturnVsinVtoVitsVfunctionVdefinitionVclearV
sin
whichVsin

built-inV(C:\ProgramVFiles\MATLAB\R2016b\toolbox\matlab\elfun\@double\sin)V %VdoubleVmethod



ScalarVOperationsVandVOrderVofVOperationsVP

roblemV2.3
CreateVMATLAB®VcodeVtoVperformVtheVfollowingVcalculations.VCheckVyourVcodeVbyVenteringVitVintoV
MATLAB®VandVperformingVtheVcalculationsVonVyourVscientificVcalculator.

5^2


ansV= 25

(5V+V3)/(5*6)


ansV= 0.26667

sqrt(4+6^3)V%Vor...


ansV= 14.832

(4+6^3)^(1/2)


ansV= 14.832
3

, 9*6/12V+V7*5^(3+2)

ansV= 21880

1V+V5*3/6^2V+V2^(2-4)V*1/5.5


ansV= 1.4621



ProblemV2.4

(a) TheVareaVofVaVcircleVis V DefineVrVasV5,VthenVfindVtheVareaVofVaVcircle,VusingVMATLAB®.


r=5


rV= 5


area=pi*r^2


areaV= 78.54


(b) TheVsurfaceVareaVofVaVsphereVisV .VFindVtheVsurfaceVareaVofVaVsphereVwithVaVradiusVofV10Vft.

r=10


rV= 10

surface_area=4*pi*r^2


surface_areaV= 1256.6


(c) TheVvolumeVofVaVsphereVisV4/3pr2.VFindVtheVvolumeVofVaVsphereVwithVaVradiusVofV2Vft.


r=2


rV= 2

volume=4/3*pi*r^3


volumeV= 33.51



ProblemV2.5
(a) TheVareaVofVaVsquareVisVtheVedgeVlengthVsquaredV(AV=Vedge2).VDefineVtheVedgeVlengthVasV5,V
thenVfindVtheVareaVofVaVsquare,VusingVMATLAB®.

edge=5


edgeV= 5
4