# Tagged Questions

Homework questions are welcome as long as they are asked honestly, explain the problem, and show sufficient effort. Please do not use this as the only tag for a question. Please do not add this tag to questions by other people unless they explicitly say that their question is part of their homework.

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### $LU$ factorization routine to solve system $Lv = f$ and $Uv = f$

I implemented an $LU$ factorization algorithm on c++ for a $n$ by $n$ matrix $A$, and I wanted to now write a routine that solves the systems $Lv = f$ and $Uv = f$. How would you recommend writing ...
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### $LU$ factorization

Our task is to implement a factorization routine that given A in a suitably efficient data structure returns the factors $L$ and $U$ where $L$ is unit lower triangular and $U$ is upper triangular. In ...
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### Understanding and implementing the Fast Fourier Transform

I need to write the fast fourier transform in C++ and I am referring to this formula from wikipedia: But for some reason I am not getting the correct output when I simply enter (1,1) (1,1) (1,1) (1,...
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### Unitary matrix representing Discrete Fourier Transform

Let $F_n\in\mathbb{C}^{n\times n}$ be the unitary matrix representing the discrete Fourier transform of length $n$ and so $F_n^{H}\in\mathbb{C}^{n\times n}$ is the inverse DFT of length $n$. For ...
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### Simpsons Rule 10<-6 Error

I am making a Java function to calculate $\int_{0}^{\pi/2}x/sin(x) dx$ using Simpsons rule. When the function equals $0$ or $0/\sin(0)$ should I just add $1$ (limit) or $10^{-10}$ (limit). My ...
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### MATLAB Physics Program to calculate distance

A raging flood washed away a section of highway, creating a gash that a car doesn't notice and goes right over the edge. Write a MATLAB program to find the distance the car travels before hitting the ...
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### My calculated laser pulse duration is too large. Where am I wrong?

I am currently writing a small Python script to estimate the pulse duration from the optical spectrum. At the end, the idea is to observe the effects of the spectral phase on the pulse duration and ...
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### How to solve this differential equation using RK4 in C++?

I have been given the following homework question to solve: I am having trouble writing a RK4 solver in C++ for this ODE. I am also not sure how to plot my solution. Here is my code so far: ...
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### Solve numerically inwards and outwards the radial equation?

We have the Schrodinger eqn $$(−\Delta+V(r))R(r)=E R(r)$$ where we can take $V(r)=-k/r$ for the beginning and we impose on the reduced radial function $u(r)=r R(r)$ the ...
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### On the cardinality of the set of numbers representable by a floating point system

I am new to numerical methods and I cannot think of a way to start solving the following problem. I know the mantissa, base and the boundaries are related when defining a number but I cannot really ...