# What is Function analysis: Definition and 21 Discussions

Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is helpful in many branches of mathematics, including algebraic geometry, number theory, analytic combinatorics, applied mathematics; as well as in physics, including the branches of hydrodynamics, thermodynamics, and particularly quantum mechanics. By extension, use of complex analysis also has applications in engineering fields such as nuclear, aerospace, mechanical and electrical engineering.As a differentiable function of a complex variable is equal to its Taylor series (that is, it is analytic), complex analysis is particularly concerned with analytic functions of a complex variable (that is, holomorphic functions).

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1. ### Kinematics: 100 meter dash when one runner starts 3 seconds later

$$t_A= 3s$$ $$s= 100m$$ $$v_A= 5m/s$$ $$v_B=7m/s$$ $$s(t)=7(t-3)+0$$
2. ### I An interesting point regarding critical points and extrema

Hi all, I have recently faced some problem about distances between two curves, and (re?)"discovered" an interesting point that I would like to share with you. In the following, we consider a function of two variables ##f(x,y)##, but it should be clear that the definitions and the result is...
3. ### I Discriminant function analysis - stepwise or otherwise?

I’m using discriminant function analysis to determine the potential accuracy of several biometric measurements being used in conjunction for binary classification purposes for my BSc Biomed research project. Overall I've only got 110 data points so it's a stretch but hey, that's anatomy! What...
4. ### Finding range of a function using inequalities

My attempt : Given ##f(x)## and ##g(x)## for ## -1.6 < x < 1.6## we get ##0\leq f(x)<1.6## Thus, for ##f(g(x))## we get ## -3 \leq g(f(x)) < -1.4## Thus the required set should be the interval ##[-3, -1.4)##? My Questions : 1. What have I missed since my answer does not match the given...
5. ### Finding the range of a function when checking if it is bijective

To check if it is injective : ##h'(x) = 3(x^2-1)## ##\implies h'(x) \geq 0## for ##x \in (-\infty, -1]## Thus, ##f(x)## is increasing over the given domain and thus is one-one. To check if it is surjective : Range of ##f(x) = (0, e^4]## but co-domain is ##(0, e^5]## thus the function is into...
6. ### Continuity of a function under Euclidean topology

Homework Statement Let ##f:X\rightarrow Y## with X = Y = ##\mathbb{R}^2## an euclidean topology. ## f(x_1,x_2) =( x^2_1+x_2*sin(x_1),x^3_2-sin(e^{x_1+x_2} ) )## Is f continuous? Homework Equations f is continuous if for every open set U in Y, its pre-image ##f^{-1}(U)## is open in X. or if...
7. ### Solving an Irregular Clock: No Continuous 576 Minutes

Homework Statement A clock runs irregularly but after 24 hours it has neither gained nor lost overall. Find a way the clock can run irregularly such that there is no continuous 576 minutes during which the clock shows that 576 minutes have passed. Homework Equations 24 hours = 1440 minutes and...
8. ### Parallelism of Time-varying Vectors

Homework Statement This is a solved problem, but I haven't understood a few things. I've marked out sections of the solution in white for convenience. The markings are positioned where that particular section ends. In part (1), how did they just assume f1(0) = 2, f2(0) = 3, g1(0) = 3, g2(0)...
9. ### Find f(x) which satisfies this integral function

Homework Statement find f(x) which satisfies f(x) = x + ##\frac{1}{\pi}## ##\int_{0}^{\pi} f(t) \sin^2{t} \ d(t)## Homework EquationsThe Attempt at a Solution to solve f(x), I have to solve the integral which contains f(t). And f(t) is the f(x) with variable t? if yes, I will get integral...
10. ### Rigor in Quantum physics -- Do I need to know Functional Analysis well?

Hello, I've a following question: Is necessary know well func. analysis, and all its theorems to handle well quantum physics...?
11. ### I Metrics which generate topologies

Given a topological space ##(\chi, \tau)##, do mathematicians study the set of all metric functions ##d: \chi\times\chi \rightarrow [0,\infty)## that generate the topology ##\tau##? Maybe they would endow this set with additional structure too. Are there resources on this? Thanks
12. ### How Do You Draw a Function from Its Equation?

Homework Statement I need to draw this function: however I don't get how? I have the solution but I don't understand how do I get that from the given function. Someone please try to explain? Thanks
13. ### B Difference between these functions .

What's the difference between f(x)=3 and f(x)=3x^0 ? and why Limit of the second function when x\rightarrow0 exists ? and is the second function continuous at x=0 ?
14. ### Solving cos(θ)^x+sin(θ)^x=1 for x: How many real solutions exist?

Homework Statement cos(θ)^x+sin(θ)^x=1 find the number of real values of x satisfying this equationHomework Equations noneThe Attempt at a Solution the answer given is 1 which is 2.which is obvious but i don't know how to prove that it is the only solution available
15. ### Creation Operator is not a densely defined operator....

Hi everyone, I am currently preparing myself for my Bachelor thesis in local quantum field theory. I was encouraged by my advisor to read the books of M. Reed and Simon because of my lag of functional analysis experience but I have quite often problems understand the “obvious” conclusions. For...
16. ### Integration of a function that's non-zero at one point

Say we have a function of the form f(x)=\bigg\lbrace\begin{matrix}c \qquad\quad\text{x=0}\\ 0\quad\text{elsewhere}\end{matrix} If we then integrate this over all space i.e. \int_{-\infty}^{\infty}f(x)dx Why does the result equal zero?
17. ### Need help with Schrödinger and some integration

My wave function: ##\psi_2=N_2 (4y^2-1) e^{-y^2/2}.## Definition of some parts in the wavefunction ##y=x/a##, ##a= \left( \frac{\hbar}{mk} \right)##, ##N_2 = \sqrt{\frac{1}{8a\sqrt{\pi}}}## and x has an arrange from ##\pm 20\cdot 10^{-12}##. Here is my integral: ##<x^2> =...
18. ### Band Pass Filter Transfer Function Analysis

Homework Statement A band Pass filter is given with the following configuration, R-Resistor, C-Capacitor: See Attatchment 1 - Circuit.jpg https://www.physicsforums.com/attachment.php?attachmentid=16241&stc=1&d=1225999965 R1 = R2 = 10 kΩ C1 and C2 are unknown Cut off Frequencies...