The Complex Derivative at a Point and Analyticity

Click For Summary
SUMMARY

The function f(z) = xy + i(xy+x) has a derivative at the specific point z = -1/2 - i/2, where the derivative is calculated as f' = -1/2 + i/2. However, the function is not analytic at this point. The Cauchy-Riemann (C-R) equations, which relate the partial derivatives of a complex function, indicate that for a function to be analytic (holomorphic), these equations must be satisfied, which is not the case here.

PREREQUISITES
  • Understanding of complex functions and their derivatives
  • Familiarity with Cauchy-Riemann equations
  • Knowledge of analytic functions and their properties
  • Basic skills in complex number arithmetic
NEXT STEPS
  • Study the Cauchy-Riemann equations in detail
  • Learn how to determine the analyticity of complex functions
  • Explore examples of functions that are analytic and those that are not
  • Practice calculating derivatives of complex functions at specific points
USEFUL FOR

Students studying complex analysis, mathematicians interested in the properties of analytic functions, and educators teaching the fundamentals of complex derivatives.

stihl29
Messages
24
Reaction score
0

Homework Statement


f(z) = xy + i(xy+x)

has a derivative at exactly one point after locating the point find the derivative there and give the numerical value is the function analytic at this point?


Homework Equations



My C-R equations are du/dx = y, dv/dy = x, dv/dx = y+1, du/dy = x

The Attempt at a Solution


i don't really know how to interpret the C-R equations.
answer is z = -1/2 - i/2 f ' = -1/2 + i/2 and not analytic
 
Physics news on Phys.org
CR actually means a relation satisfied by the partial derviatives for a complex function to be analytic (holomorphic)

you have only given the partial derivatives, do you know the CR equations?
 

Similar threads

Replies
19
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
Replies
3
Views
2K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
1
Views
2K
  • · Replies 25 ·
Replies
25
Views
2K
Replies
6
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K