Here’s a persuasive advertisement for ghostwriting services specifically for the topic of Euler’s formula:
**Unlock the Secrets of Euler’s Formula with Our Expert Ghostwriting Services**
Are you struggling to grasp the intricacies of Euler’s formula, a mathematical gem that connects 5 fundamental constants (0, 1, i, π, e) and 3 key operations? Do you need help with your assignment, essay, or research paper on this fascinating topic?
Our team of expert ghostwriters, comprised of seasoned mathematicians and writers, can help you unlock the full potential of Euler’s formula. With our comprehensive ghostwriting services, you can expect:
* In-depth research and analysis of Euler’s formula, covering arithmetic, algebra, geometry, and analysis
* Clear and concise explanations of complex mathematical concepts, tailored to your academic level
* Well-structured and engaging writing that showcases your understanding of the topic
* Accurate and timely delivery of your assignment, ensuring you meet your deadlines
Our advantages:
* Expertise in mathematics and writing, guaranteeing high-quality content
* Fast turnaround times, without compromising on quality
* Confidentiality and security, ensuring your academic integrity
* Competitive pricing, without sacrificing excellence
Don’t let Euler’s formula intimidate you. Let our expert ghostwriters help you shine in your academic pursuits. Order now and experience the difference!
**Get a quote today and take the first step towards academic success!**
Note that _Euler’s formula_
\[e^{\pi i}+1=0\]
connects the five most important constants of mathematics, symbolizing the four major branches of classical mathematics:
* Arithmetic represented by \(0\) and \(1\)
* Algebra by \(i\)
* Geometry by \(\pi\)
* Analysis by \(e\)
This formula also contains three of the most important operations: addition, multiplication, and exponentiation.
### Geometry in the Complex Plane
Many subsets of \(\mathbb{C}\) that appear repeatedly later on are described below.
* For \(z,w\in\mathbb{C}\), the _line segment_ with end points \(z\) and \(w\) is given by \[[z,\ w]=\{(1-t)z+tw:\quad 0\leq t\leq 1\}.\]
* The _real axis_ can be given by any of the following equations:
Similarly, the imaginary axis can be described as \(\operatorname{Re}z=0\) or \(|z-1|=|z+1|\) (Figure 3.4).
Figure 3.3: Some complex numbers
[MISSING_PAGE_FAIL:290]
[MISSING_PAGE_FAIL:291]
[MISSING_PAGE_EMPTY:615]
In order to understand the above property we examine the complex exponential function in detail later in Section 3.4.
### Arithmetic of Complex Numbers
The real part of a complex number \(z=a+ib\) is \(a\) and is denoted by \(\operatorname{Re}z\), and the number \(b\) is called the imaginary part of \(z\) and is denoted by \(\operatorname{Im}z\). For example, \(\operatorname{Re}(3+2i)=3\) and \(\operatorname{Im}(1-5i)=-5\). Two complex numbers are considered equal if and only if their real and imaginary parts are equal, that is,
\[a+bi=c+di\quad\text{if and only if}\quad a=c\quad\text{and}\quad b=d.\]
Complex numbers are added, subtracted, and multiplied in accordance with the standard rules of algebra but with \(i^{2}=-1\):
\[(a+bi)+(c+di) =(a+c)+(b+d)i,\] \[(a+bi)-(c+di) =(a-c)+(b-d)i,\] \[(a+bi)(c+di) =(ac-bd)+(ad+bc)i.\]
Also note that if \(b=0\), then the multiplication formula simplifies to
\[a(c+di)=ac+adi.\]
The product of a complex number \(z=a+bi\) and its _conjugate_\(\overline{z}=a-ib\) is a non-negative real number:
\[z\overline{z}=(a+bi)(a-bi)=a^{2}-abi+bai-b^{2}i^{2}=a^{2}+b^{2}.\]
Note that complex conjugate of \(z\) in the polar form \(z=re^{i\theta}\) is \(\overline{z}=re^{-i\theta}\). You will recognize that
\[|z|=\sqrt{z\overline{z}}=\sqrt{a^{2}+b^{2}}\]
is the length of the vector corresponding to \(z\); we call this length the _modulus_ (or absolute value) of \(z\) and denote it by \(|z|\). For example the modulus of \(z=-4-5i\) is \(|z|=\sqrt{(-4)^{2}+(-5)^{2}}=\sqrt{41}\).
If \(z\neq 0\), then the _reciprocal_ (or multiplicative inverse) of \(z\) is denoted by \(1/z\) (or \(z^{-1}\)) and is defined by the property
\[\left(\frac{1}{z}\right)z=1.\]
This equation has a unique solution for \(1/z\), which can be obtained by multiplying both sides by \(\overline{z}\) and using the fact \(z\overline{z}=|z|^{2}\). This yields the expression
\[\frac{1}{z}=\frac{\overline{z}}{|z|^{2}}.\]If \(z_{2}\neq 0\), then the _division_\(z_{1}/z_{2}\) is defined as the product of \(z_{1}\) and \(1/z_{2}\), and thus
\[\frac{z_{1}}{z_{2}}=\frac{\overline{z_{2}}}{|z_{2}|^{2}}z_{1}=\frac{z_{1} \overline{z_{2}}}{|z_{2}|^{2}}.\]
Note that the expression on the right-hand side of the above equation can be viewed as both the numerator and denominator of \(z_{1}/z_{2}\) multiplied by \(\overline{z_{2}}\).
**Example 96**.: Let \(z_{1}=3+4i\) and \(z_{2}=1-2i\). To find \(z_{1}/z_{2}\) we will multiply the numerator and denominator of \(z_{1}/z_{2}\) by \(\overline{z_{2}}\).
\[\frac{z_{1}}{z_{2}} =\frac{z_{1}\overline{z_{2}}}{z_{2}\overline{z_{2}}}=\frac{3+4i} {1-2i}\frac{1+2i}{1+2i}\] \[=\frac{3+6i+4i+8i^{2}}{1-4i^{2}}\] \[=\frac{-5+10i}{5}\] \[=-1+2i.\]
The following identities hold for all \(z,w\in\mathbb{C}\):
1. \(\overline{\overline{z}}=z\).
2. \(\operatorname{Re}z=\frac{z+\overline{z}}{2}\) and \(\operatorname{Im}z=\frac{z-\overline{z}}{2i}\).
3. \(|\overline{z}|=|z|\).
4. \(|z|^{2}=z\cdot\overline{z}\).
5. \(\overline{zw}=\overline{z}\cdot\overline{w}\).
6. \(\overline{z+w}=\overline{z}+\overline{w}\).
**Remark.** The set of complex numbers, denoted \(\mathbb{C}\), form a field; in fact, the complex numbers are an _algebraically complete_ field, meaning that every polynomial with complex coefficients has a complex root. In fact, we have the following important theorem.
**Theorem 120**.: _(Fundamental Theorem of Algebra) Every polynomial of degree \(n\) with complex coefficients has \(n\) complex roots, counted with multiplicity._
For the proof we refer the reader to Theorem 137 in Section 3.8 below.
The Fundamental Theorem of Algebra is an existence theorem and does not tell you a method for finding zeros. For polynomials of degree \(2\), quadratic formula gives the zeros explicitly. Similar but more complicated formulas exist for polynomials of degree \(3\) and \(4\). No such formulas exist for polynomials of degree \(5\) and higher. The Fundamental Theorem of Algebra fails in \(\mathbb{R}\). This difference accounts for the differences between operators defined real and complex vector spaces.
### Products and Powers; de Moivre’s Theorem
There are certain polynomials which occur repeatedly in complex analysis. It is essential to became familiar with these polynomials and the location of their roots. First notice that the polar form of a nonzero complex number of the _exponential form_
\[z=re^{i\theta}=r\cos\theta+ir\sin\theta\]
enables us to multiply two complex numbers, say \(z=r(\cos\theta+i\sin\theta)\) and \(w=\rho(\cos\psi+i\sin\psi)\). We have
\[z\,w=r\,\rho[(\cos\theta+i\sin\theta)\,(\cos\psi+i\sin\psi)]=r\rho\cos(\theta+ \psi)+ir\rho\sin(\theta+\psi)\]
by the standard trigonometric formulas, thus
\[z\,w=r\,\rho\,e^{(\theta+\psi)}.\]
This implies in particular that \(\left|z\,w\right|=\left|z\right|\left|w\right|\). Let \(z=re^{i\theta}\) and \(n\) be a natural number, then from the above and a routine proof by induction, we obtain
\[z^{n}=r^{n}\,e^{in\theta}.\]
In the special case \(r=1\) we obtain _de Moivre’s theorem_:
发表回复