Questions tagged [homework]

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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28
votes
4answers
20k views

Finding unit tangent, normal, and binormal vectors for a given r(t)

For my Calc III class, I need to find $T(t), N(t)$, and $B(t)$ for $t=1, 2$, and $-1$, given $r(t)=\{t,t^2,t^3\}$. I've got Mathematica, but I've never used it before and I'm not sure how to coerce ...
12
votes
8answers
4k views

How to make a resizable chess board?

For some reason I need to create a chess board. I can create a chess board by following command: ...
8
votes
4answers
712 views

Generating a polynomial that's accurate to within an error of no more than 1/10^5

I'm currently stuck on a question for class that asks... "Find a polynomial p[x] that you can use to calculate 6 ArcTan[x] to ...
8
votes
2answers
548 views

Check homework integration in Mathematica

Given in my homework I have to compute (by hand) $$\iint\limits_{x^2+y^2\leq 1}(x^2+y^2)\,\mathrm dx\,\,\mathrm dy.$$ My solution so far: Let $f(x,y)=x^2+y^2$ and $K=\{(x,y)\in\mathbb{R}^2:x^2+y^2\leq ...
8
votes
3answers
9k views

I want to draw a graph using a weighted Adjacency matrix

I have a weighted adjacency matrix as follows: ...
6
votes
1answer
103 views

NumericQ exercise in Wagner

I've been thinking about this exercise in Wagner (p. 269), but I can't answer. Can you tell me?
5
votes
1answer
462 views

An efficient way to translate a triple for-loop from Matlab to Mathematica

This is my first post on StackExchange, so if I violate any etiquettes, I apologize in advance. I am a senior engineering student who has been using Mathematica for a year now. For one of my classes, ...
5
votes
1answer
296 views

PearsonChiSquareTest: set degrees of freedom

How to set degrees of freedom for PearsonChiSquareTest? I have this: ...
5
votes
1answer
1k views

How to plot the solution of a Partial Differential Equation?

My attempt. I need to solve numerically the Complex Ginzburg-Laudau Equation (CGLE): $$ \frac{\partial A}{\partial t}=\epsilon A-(1+i\beta)|A|^2A+(1+i\alpha)\nabla^2A $$ I'm using a uniform initial ...
4
votes
4answers
6k views

The Lotka-Volterra predator-prey model

I have a Mathematica assignment where we need to numerically solve a Lotka-Volterra predator-prey population equations. $$\frac{dx}{dt}=ax-bxy,\quad\frac{dy}{dt}=-cx+dxy,$$ where $a,b,c,d\in\mathbb{R}...
4
votes
3answers
506 views

Area of volume of revolution

I want to calculate the exact area of this volume: RevolutionPlot3D[ f[x_] = Sqrt[28 x] , {x, 0, 21} , Axes -> True ] Additionally, I wish to see $x$ and $...
4
votes
2answers
218 views

How to check whether Laguerre polynomials are orthogonal?

I've got the problem with checking if Laguerre polynomials for n=1,...,10 are orthogonal. I have to create the list of these polynomials, then create the matrix of integrals from 0 to infinity. ...
4
votes
2answers
277 views

Strange determinant result

I carried out the determinant of a $4\times4$ matrix in two different ways: with Laplace and without Laplace (see this attachment please). The Laplace's rule is applied "manually" in Mathematica (I ...
4
votes
1answer
257 views

Particle moving on curve which is the intersection of a surface and a plane

Surface z = 2 x^3 - 5 y^4 Plane z = x + y + 5 Plot A curve is formed by the intersection of the surface and the plane. I ...
4
votes
3answers
336 views

Dot products and For-loops

I'm taking a class where we're working with matrix applications inside of Mathematica. In this case, we're analyzing senatorial votes that have been numericized so that a value of 1 corresponds to "...
4
votes
2answers
198 views

Use Select to filter a dataset's sublists

In the following Dataset, I want to use Select to display only rows, which contain numbers in column ...
4
votes
1answer
448 views

How can I make a pretzel shape using Bézier curves?

I am trying to make a pretzel shape,but I cannot seem to get the loops even. Eventually, I need to make the pretzel shape loop in 3D so I need to nail the 2D concept first. Here's what I have so far....
4
votes
1answer
92 views

Dynamics problem [closed]

This is school work. I do not want the problem solved for me, but I just want to know what I did wrong with my ParametricPlot. Question: A material point moves ...
4
votes
3answers
424 views

Minimizing Multiple Functions

I'm trying to write a script that will minimize a given set of functions. The homework problem I've been given lists a set of dietary information, and I'm supposed to build the optimal salad based on ...
4
votes
1answer
190 views

Extraction of rows with even numbers of a dataset

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3
votes
2answers
376 views

Plotting the solutions of $y' = -\frac{\cos y}{\sin x}$

I struggle with the problem of plotting the solution of this ODE: $\qquad y' = -\frac{\cos y}{\sin x}$ I've already tried to use ContourPlot in a loop and in a ...
3
votes
2answers
603 views

For Loop and Sum

I am requested to do a sum of the first fifty positive even numbers by using For loop. The For loop that I created is ...
3
votes
2answers
266 views

Exercise using Sort

I have to order the following list according to the sum of the powers of each element of the list, using the function Sort. ...
3
votes
4answers
469 views

Print all numbers from a sequence which don't contain the digit 7

so i have this: Cases[RecurrenceTable[{a[n + 1] == 7 a[n] + n, a[1] == 1}, a, {n, 7}], Except[7]] But i noticed that it will only exclude numbers that are 7, and ...
3
votes
3answers
150 views

Infinite While loop

I have an exercise where I need to input a multi-digit number and evaluate the square of the sum of its digits. I am new to Mathematica and I can't figure out why I'm getting an infinite loop. This is ...
3
votes
1answer
138 views

How do I plot a Laplace transform?

I have been looking everywhere for help on this issue and cannot find a solution that works. Here is the assignment. I have figured out how to find the Laplace transform, but I do not know how to ...
3
votes
4answers
195 views

Implicitly defined curve

Consider the curve $C$ defined by the equation $y\, \sin(x)+x\, \sin(y)+x+y=0$. Find all points of the form $(8,y)$ that lie on $C$. For each point found in part 1, evaluate the derivative $dy/dx$...
3
votes
2answers
138 views

How to find $\delta$ for limit type questions

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3
votes
1answer
301 views

Using single replacement rule to convert algebraic expression

I have been trying this problems for hours and cannot find any helpful clues. How can I convert $Sinh[3\theta]+Sinh[\theta]$ to a rational function of x given $2Sinh[\theta] = x-x^{-1}$ by using only ...
3
votes
1answer
137 views

Tower of Hanoi list of disks on the rods

I'm currently trying to finish a program that outputs the "radius" of each disk on each rod in lists. I currently wrote this program: ...
3
votes
1answer
116 views

UnitStep in Mathematica when t varies differently

How can I use the UnitStep command when I have a piecewise function $f(t)$, where $f(t)= 0$, when $|t|>4$, and $f(t)=1$, when $|t|<4$? I tried with ...
3
votes
1answer
249 views

Newton's Method

Problem statement: I'm currently new to Mathematica and have been trying to solve this problem. I was digging around and found this code: ...
3
votes
1answer
239 views

Formatting ANOVA table and/or ParameterTable without using Grid?

Does anyone know if there is an option or function that can automatically format the output of ANOVATable and ParameterTable, ...
3
votes
0answers
60 views

Plotting gradient and newton directions for parametric system of nonlinear ODEs

I have a bucket (system) of chemical kinetics models, a nonlinear dynamical system given by: where kf >= 0 and kr >= 0 are the parameters. The initial conditions are A(0) = B(0) = 1 and C(0) = 0. I'...
3
votes
0answers
149 views

Writing a function to set up and solve the least squares problem

I have setup the explicit line equation for a given set of points using least-squares approximation and the knots computed below. I have tried extending the same code for use with an arbitrary degree, ...
2
votes
3answers
2k views

draw part of parabola using graphics

Today, I was doing my physics homework. One of the questions was to draw velocity-time and position-time graphs from the acceleration-time graph. So for the first step I draw acceleration-time using <...
2
votes
1answer
1k views

Using triangulation

I have been presented with 3 known points and the power densities at those points. I need to use those points to find the location of the actual antenna which is generating the signals. Power ...
2
votes
3answers
909 views

Write program to check if an integer is divisible by 2, 3 and 5 [closed]

Write a program to check if an integer is divisible by either 2, 3 or 5. If an integer is divisible more than one of these numbers it should also show all of them. For example: 8 is divisible by ...
2
votes
2answers
2k views

Using the epsilon tensor in Mathematica

I'm having a great deal of trouble getting started on a weekly homework assignment in Mathematica. The assignment requires we use the epsilon tensor which is apparently built into Mathematica as ...
2
votes
2answers
428 views

local variable naming & symbolic argument

I'm stuck here with my variable assignment in this scenario ...
2
votes
2answers
154 views

Euler's method initial value problem — how should I plot the solution?

We are given the following initial value problem: $\qquad y' = t\,e^{3\,t} -2\,y, \quad 0 \le t \le 1, \quad y(0)=0$ Use Euler`s method to approximate the solution to this initial value problem. In ...
2
votes
3answers
189 views

Finding primes that have certain property

Let S[p] denote the sum of digits of p. A prime p is said to be stubborn if none of ...
2
votes
2answers
90 views

Illustrate homework (integral region with implicit region)

I must integrate: $$ \int \int_D x^2y^2 dx dy$$ in the first quadrant. This is a triangle with vertices in $(0,0)$, $(0,1)$ and $(1,0)$. I tried to draw it in mathematica with implicit region: <...
2
votes
3answers
1k views

Parametric Curves Tangent Line

Find an equation to the tangent of the curve at the given point. Then graph the curve and the tangent. $$x=t^2-t,\quad y=t^2+t+1; \quad(0,3)$$ I can do this with a simple $f(X)$ function but the ...
2
votes
2answers
717 views

Plot: 2D potential vortex embedded in 2D uniform flow

Consider a 2D potential vortex (having velocity $u_\theta = c/r$ in a quiescent environment) embedded in a 2D uniform flow (having a velocity of $u_x= U$ far away from the vortex) as below: Question: ...
2
votes
2answers
82 views

Inserting an integer into a list while maintaining descending order

Define a function g with two arguments, w and n, where w ...
2
votes
1answer
294 views

Plotting and ContourPlot

Make a Plot and a ContourPlot that gives the same diagram and use ContourPlot on a quadruple ...
2
votes
2answers
1k views

Using RegionPlot3D to make a cone under restrictions

I have to plot a cone that satisfies this statement: Use the RegionPlot3D command to draw a picture of a cone with its point at the origin. The other end of the cone is a circle with radius 5 ...
2
votes
1answer
541 views

Getting the 557th element of a table

Make a table with elements $\sin(\sqrt{8 n}/4) + r\, $for $n$ from $1$ to $1000$, where $r$ is a random real number between $-0.1$ and $0.1$ that is different for each value of $n$. Also make a plot ...