Transcription of 5.3 Determinants and Cramer’s Rule - Math
{{id}} {{{paragraph}}}
Determinants and cramer s RuleUnique Solution of a2 2 SystemThe 2 2 systemax+by=e,cx+dy=f,(1)has a unique solution provided =ad bcis nonzero, in which case thesolution is given byx=de bfad bc, y=af cead bc.(2)This result, calledCramer s Rulefor 2 2 systems, is usually learnedin college algebra as part of determinant of Order2 College algebra introduces matrix notation and determinant notation:A=(a bc d),det(A) = a bc d .Evaluation of a 2 2 determinant is bySarrus Rule: abcd =ad boldface productadis the product of the main diagonal entries andthe other productbcis from the s 2 2 rule in determinant notation isx= e bf d a bc d , y= a ec f a bc d .(3)Unique Solution of ann nSystemCramer s rule can be generalized to ann nsystem of equationsA~x=~bora11x1+a12x2+ +a1nxn=b1,a21x1+a22x2+ +a2nxn=b2,..an1x1+an2x2+ +annxn=bn.(4) Determinants and cramer s Rule291 System (4) has a unique solution provided thedeterminant of coeffi-cients = det(A) is nonzero, in which case the solution is given byx1= 1 , x2= 2.
5.3 Determinants and Cramer’s Rule 293 It is known that these four rules su ce to compute the value of any n n determinant. The proof of the four properties is delayed until page 301. Elementary Matrices and the Four Rules. The rules can be stated in terms of elementary matrices as follows. Triangular The value of det(A) for either an upper ...
Domain:
Source:
Link to this page:
Please notify us if you found a problem with this document:
{{id}} {{{paragraph}}}