
EEL3105Fall2011
Homework6
Note:Problem4willbegradedseparatelyforassessingthatoneofthecourseobjectivesis
met.PleasesubmitsolutiontoProblem4asaseparatedocument.
Considermatrices
12
123
13
4
01
010
001
Ak
Bbb
C
ccc
1. ForA,choosek=3.Findtheeigenvaluesoftheresultingmatrix.Aretheyreal?Why?
2. FindaformulaforeigenvaluesofAasafunctionofk.Supposekisadesignparameter
whichrangesfrom‐100to+100.UsetheformulatoplottheeigenvaluesofAasafunction
ofkinthecomplexplane.UseMATLABtoverifyyouranswer.Suchaplotiscalledroot
locus.Commentonyourresults.
3. FindcharacteristicpolynomialsofBandCintermsofb1,b2,c1,c2,andc2.Doyouseeany
patterninyouranswer?Canyouthinkofawaytogeneralizethistoannxnmatrix?
4. Fixb2=1.Supposeb1beadesignparameterthatrangesfrom0to100.Itmayrepresentthe
valueofaphysicalcomponent(e.g.,massorresistance).FindtheeigenvaluesofBasa
functionofb1andplottheminthecomplexplane.Commentonyouranswer.Supposefor
certaindesignconsiderations(havingtodowithtransientresponse),wewanttheangleof
theeigenvaluestobe3/4.
Choosethevalueofthedesignparameterb1tosatisfythis
constraint.
5. LetAbeannxnmatrix.ShowthateigenvaluesofAarethesameasthoseofAT.
6. Considermatrices
12
45
31
369
248
A
B