Terrifying question about polynomial in analysis

In summary, the textbook explains that a non-constant analytic polynomial cannot be real-valued because it would not satisfy the Cauchy-Riemann equations. This is illustrated by the example of a polynomial with a real-valued partial derivative with respect to x and y, but a constant imaginary component. The reason for this is not explained in the book.
  • #1
eileen6a
19
0
the textbook says that:
"a non-constant analytic polynomial cannot be real-valued, for then both the partial derivative with respect to x and y would be real and the cauchyriemann equation cannot be satisfied."
why??there's no explanation in the book and this sentence is written as an example.
help.
 
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  • #2
Well let's see what we got:

[tex]
\begin{aligned}
f(z)&=P_n(z)=u(x,y)+iv(x,y) \\
&=u(x,y)+i0\\
&\neq k
\end{aligned}
[/tex]

So then:

[tex]\begin{aligned}
\frac{\partial u}{\partial x}&=g(x,y) &\quad \frac{\partial u}{\partial y}&=h(x,y)\\
\frac{\partial v}{\partial x}&=0 &\quad \frac{\partial v}{\partial y}&=0
\end{aligned}
[/tex]

. . . so if f(z) is not equal to k (a constant) . . . then what?
 
  • #3
thanks you must be a genius
 

FAQ: Terrifying question about polynomial in analysis

1) What is a polynomial?

A polynomial is an algebraic expression that consists of one or more variables raised to non-negative integer powers and multiplied by coefficients. It is a fundamental concept in algebra and is used to represent a wide range of mathematical functions.

2) What is analysis?

Analysis is a branch of mathematics that deals with the study of continuous change and related concepts such as limits, derivatives, and integrals. It is used to understand the behavior and properties of functions and their graphs.

3) How are polynomials used in analysis?

Polynomials are used in analysis to approximate more complex functions. By using polynomials, we can break down a complicated function into simpler pieces, making it easier to analyze and understand.

4) What makes a polynomial a terrifying question in analysis?

The term "terrifying" is subjective, but polynomials can be challenging in analysis because they can have infinitely many terms, making them difficult to work with and analyze. They can also exhibit complex and unpredictable behavior, adding to the difficulty of understanding them.

5) What are some applications of polynomials in analysis?

Polynomials have numerous applications in analysis, including in physics, engineering, economics, and computer science. They are used to model and solve real-world problems, such as predicting the trajectory of a projectile or optimizing a financial portfolio.

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