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Chap 4. Complex Algebra. For application to Laplace Transform Complex Number. Argand Diagram. y. r. q. x. Complex Variables. Continuous Function. Cplxdemo.m. Single Value Function. Many Values Function. Derivatives of Complex Variables. 1. 0. 0. 1. Cauchy Riemann Conditions.
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Chap 4 Complex Algebra
For application to Laplace Transform • Complex Number
Argand Diagram y r q x
Complex Variables Continuous Function Cplxdemo.m
Single Value Function Many Values Function
0 1 Cauchy Riemann Conditions
Analytic Functions It has single value in the region R It has a unique finite value It has a unique finite derivative at z0, satisfies the Cauchy Riemann Conditions
Example Cauchy Riemann Conditions
Keep y constant At Origin One_OVER_Z.m
Singularities Poles or unessential Essential Branch points
Poles or unessential Singularities Second order Poles Pole at a Pole order p at zero Pole order q at a
Essential Singularities E_1_z.m
Branch Points Many Value Function Single
Cauchy’s Theorem ถ้ามีฟังก์ชั่นใดที่เป็น Analytic ภายในหรือบน closed contour, integration รอบ contour จะได้ศูนย์ Stake’s theorem Cauchy – Riemann conditions integral ทางด้านขวามือจะเป็นศูนย์
ตามเส้นทาง AB หรือ รอบเส้นทาง ACDB path AB
curve ACDB 1. ตาม AC
2. เส้นโค้ง CDB ซึ่งมี constant radius 10 ผลรวมของ Integral
Example 2 Evaluate around a circle with its center at the origin. Although the function is not analytic function
Example 3 Evaluate around a circle with its center at the origin. This result is one of the fundamentals of contour integration
Cauchy’s Integral formula f(a) =constant at g
The theory of Residue Pole at origin Laurent expansion
Example 1 Evaluate Around a circle center at the origin if Function is analytic There is a pole order 3 at z = a if
Evaluation without Laurent expansion Many poles : independently evaluate
Example 2 Evaluate the residues of Poles at 3,-4 Sum of Residues = 1
If the denominator does not factorize L’Hopital’s rule
Example 4 evaluate Around circle and Pole at z = 0
Multiple Poles Dividing throughout by