Questions regarding the plotting or graphing of functions. Questions about graphs with vertices and edges should use the (graph-theory) tag instead. (STUB)

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1answer
22 views

Plot a fourier series

I'm not a mathematician but I hope my question is easily answered. I'm trying to learn about graphing equations in a computer application (I'm a programmer). From this link a fourier series is ...
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1answer
24 views

Predict the nature of the curve

$$f(x)=\int_0^{\sqrt{x}}e^{u^2\over x}du$$ Hence predict the graph of $f(x)$:
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0answers
49 views

$x^{y}=y^{x}$ Intersection Question

I'm looking at this problem, $x^{y}=y^{x}$ and the question is to find the point of intersection of the two curves that form a solution set. I understand how to find the point of intersection using a ...
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0answers
13 views

Shape of graph and plot

Suppose $x \in [0, \infty)$ and $y \in [-1,1]$. When we plot $y$ vs. $x$, we get an upward parabola shape. Suppose we plot $y^2$ vs. $x$. Would the shape also be approximately an upward parabola?
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5answers
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Points on $(x^2 + y^2)^2 = 2x^2 - 2y^2$ with slope of $1$

Let the curve in the plane defined by the equation: $(x^2 + y^2)^2 = 2x^2 - 2y^2$ How can i graph the curve in the plane and determine the points of the curve where $\frac{dy}{dx} = 1$. My work: ...
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4answers
95 views

Understanding the graph for $x^y = y^x$

I graphed $x^y=y^x$ and it is a union of the line y=x, with some other curve. So my first question is, how do I derive that other curve? My next question is, why don't I get the same graph when I ...
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1answer
25 views

Mathematics to compare points

I am not sure if this a question for the mathematics stackoverflow or some other. If it is then please move it. Basically, I have a programming challenge where given list of points (which form a line ...
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1answer
46 views

Sketching the spectrum of a signal

The figure below shows Fourier spectrum of a signal $g(t)$ Sketch the spectrum of the signal $2g(t)\cos^2(100\pi t)$. Show value in sketch.
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2answers
63 views

Strange graph problem

I'm trying to figure out this question: in the Cartesian coordinate system, how many grid points (x,y) satisfy $(|x|-1)^2 + (|y|-1)^2 < 2$? When I plugged it in to a graphing calculator, it didn't ...
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3answers
31 views

Graphing a Circle that doesn't have two of each variable

Graph the circle: $$x^2+y^2-2x-15=0$$ I know how to approach this problem if there were two $y$ and $x$ variables. But there is only one $y$ variable. How would I approach this?
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1answer
87 views

How do you minimize “hinge-loss”?

A lot of material on the web regarding Loss functions talk about "minimizing the Hinge Loss". However, nobody actually explains it, or at least gives some example. The best material I found is here ...
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0answers
29 views

How to find change points in a graph on matlab

I have a graph like this I need to find points at which sudden changes happening for the DPC Time Curve. We can observe that at time 20 and around 70 increase is happening. How to do this in Matlab. ...
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1answer
25 views

Curve Sketching - transforming f(x) to f(a-x)

In class I learnt that to sketch $y=f(a-x)$ given a graph of $y=f(x)$, you reflect the given graph about the line $x=a/2$ (this was proven to us). And then the teacher said that something we ...
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1answer
65 views

Is there closed form for $(1-p)(1-p^2)(1-p^3)…$ or its Taylor expansion?

I was considering the following problem: Somebody uses a backup for something (e.g. backups a file) and the backup is equally reliable as original storage. The storage is not perfectly reliable and ...
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0answers
6 views

Steps in Anlaysing Surface Plot

I have two vectors ${\bf x}$, ${\bf y}$ such that $0 \leq x_i, y_j \leq 1$ and a third vector ${\bf z}$ where $z_i \in \{0,1\}$. Each row of the vectors represents an 'observation' and I am trying to ...
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3answers
57 views

Find the locus of points

Find the locus of points, the distance between them and the point $(2,1)$ is equal to the distance between them and the straight line $4x = 3y$ I know that it is the definition of a parabola But I ...
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2answers
54 views

What is graph of graph of $y = (x-1)\sqrt{x}$

The book "A student's Guide to Fourier Transforms" 3rd edition, by J.F.James, published by C.U.P., on pages 20 and 21 quotes the equation $y = (x-1)\sqrt{x}$ as an example of one that does not meet ...
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0answers
35 views

How do I convert a function $f(x)$ to $f(\frac{x}{a})$?

I have a pretty simple problem but I kinda am confused. I have the function $$f(x)_a = \sqrt{\frac{2}{\pi}} \cdot \frac{Aa}{x^2 + a^2}$$ And especially: $$f(x=0)_a = \sqrt{\frac{2}{\pi}}\cdot ...
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2answers
33 views

creating graphs in wolfram alpha

I am trying to plot the function $$\max(x-40,0)$$ in Wolfram|Alpha, but I can't figure out how. What Wolfram|Alpha query URL should I use to produce this graph? Or, what similar online program could ...
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1answer
24 views

Sine Graphs Equation Meaning

What do each of these numbers mean in this equation for sine graphs? y = -3sin[2(x-30)] + 1 I know 1 = shift up What does the rest mean? thanks.
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0answers
16 views

Interpreting functions of graphs

The question asked which of the following is false. I narrowed it down to two, and the correct answer is E with it doesn't cross the x-axis at all. D. f(x) * g(x) intersect the x-axis three times E. ...
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1answer
28 views

Drawing a graph of $x\cos\left(\frac 1x\right)$

I have been given a question which asks to draw the graph of $x\cos\left(\frac 1x\right)$ without a calculator. However, I'm unsure as to how to do this. It may involve differentiation as that was the ...
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2answers
13 views

Scale 'priority' where 1 is larger than 3 for graph

I simply want change a scale on graph so that 1 is largest value and three is smallest. I have data in excel. A function would preferred as I do not want to simply swap the values.
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2answers
46 views

Problem with powers

I hope this has not been asked already. while reading a material on upper bounds of polynomials (time complexity) they compared growth of various polynomial functions (like $N\log N$, $N^2$, $N^3$, ...
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1answer
32 views

description of the function whose graph corresponds to Figure

Consider f be a real continuous function , $f(0) = 0$ , and whose graph has the form shown in the figure: a) How can a give description of the function whose graph corresponds to Figure. b) Sketch ...
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0answers
17 views

Trouble calculating surface area

I am trying to calculate the surface area of a solid of revolution of f(x) about the x axis for the interval [1,6] $f(x) = \begin{cases} 1 & 1 \leq x< 2\\ 1/2 & 2 \leq x< 3\\ . ...
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1answer
28 views

Finding surface area of revolution

Can anyone help me with finding the surface area of a solid of revolution of f(x) about the x axis for the interval [1,6]. It's supposed to be able to be done without needing calculus but I am having ...
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1answer
48 views

Finding volume of the solid of revolution?

Can anyone help me with finding the volume of a solid of revolution of f(x) about the x axis for the interval [1,6]. It's supposed to be able to be done without needing calculus but I am having ...
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1answer
58 views

Drawing polar graphs when given theta in terms of the radius

I know how to plot when it is like $r=10 \cdot \sin(2\theta)$. But how to do that when the condition is like: $\theta =2 \pi \cdot \sin(r)$?
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1answer
30 views

Problem with graphing a function.

To my understanding, function $f(x)=\frac{1+x}{1+x^3}$ should not be defined with $x=-1$ since: $f(-1)=\frac{1+(-1)}{1+(-1)^3}=\frac{1+(-1)}{1+(-1)}=\frac{0}{0}$ However, Google's plot drawer and ...
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1answer
29 views

What is the domain of $Z=\sin(\ln(x\,\arccos{y}))$?

What is the domain of $Z=\sin(\ln(x\,\arccos{y}))$? I see that is should be $-\dfrac{\pi}{2}\leq \ln(x\,\arccos{y}) \leq \dfrac{\pi}{2}$ and then $e^{-\dfrac{\pi}{2}} \leq x*\arccos(y) \leq ...
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3answers
36 views

What is the domain of $z=\arcsin\dfrac{x}{y}$?

I get that it should be $|y|>|x|$ and in the Wolfram it looks like this. But when I graph it by hand is that it should be only the "upper" part of intersection and not the "bottom" part as well, ...
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1answer
21 views

Finding solutions using graph

Find the number of solutions of the equation $$|\ln|x|\;|=\sin(\pi x)$$ I know how to draw roughly the graph of $|\ln|x|\;|$. However, at $x=1$, both the graphs will pass through $(1,0)$. How do I ...
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2answers
38 views

How to plot not only the result but also the derivatives of an ode using the ode45 function in Matlab?

I have already successfully run a code for the simulation of the deflection of beams under different loadings. I used the Matlab program and the ode45 solver for Initial value Problems and bvp4c ...
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1answer
48 views

Plotting 0-360 degrees

I have some direction (bearing from north) data in degrees. Some of this data jumps between 1-360 degrees when plotted as a line graph, which is not easy to read, as the variation is actually only 1 ...
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0answers
35 views

How to approach sketching sine and cosine graphs with transformations

Any tips or suggestions in sketching these graphs quickly, and in ONE go? In exams, I don't want to spend ages re-drawing the original sine/cosine graph, one by one, following each new ...
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3answers
65 views

Plotting a region in $3D$ space

I would like to know if someone knows of a software where I can plot the following region $$ D = \{ (x,y,z) \in \mathbb{R}^3: 0 \leq x \leq 1 , \; x^2 \leq y \leq x, \; \; 0 \leq z \leq x \} $$ ...
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1answer
49 views

Matlab Cropping Plots

I want to adjust the amount of whitespace that is shown when plots are generated. I found this command to do just that: ...
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2answers
83 views

Roots of $x^4-3x^2+x-\sin x$

Is there a logical/qualitative argument to find out the number of roots of $x^4-3x^2+x-\sin x$ ? I tried plotting graphs for $x^4-3x^2+x$ and $\sin x$ to check the points of intersection but it only ...
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0answers
13 views

Question on Cobweb Diagram

Let f be a real map and assume that the points a and b form a limit cycle of order two of f. Derive a simple formula for the derivative of the second iterate of f at a.
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1answer
28 views

Choosing values for octave/decade scale

I am developing a frequency response simulator for linear circuits which should be able to plot graphs of Voltage x Frequency with the latest varying linearly, in octaves or in decades. The only ...
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2answers
44 views

Curve stretching

Let $f(x) = x^2$ Let's try to transform that to $8x^2$. First question, is this a vertical stretch scale factor $8$? That would be $8f(x)$ then? But, could it also be $f(\frac{x}{\sqrt{8}})$ because ...
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1answer
47 views

How to draw contour lines (projections) on axis x or y with octave?

With the builtin function contour(x,y,z) of octave one can draw level curves where z remains constant. My question is how to draw contour lines on axis x or axis ...
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2answers
41 views

How do you shift a sigmoidal curve to the right?

How do you shift the function $1$ $/ ( 1 + e ^ {-x} )$ to the right without altering the shape of the curve?
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4answers
47 views

Equation of a line

I've been practising some past previous exam question and came across this: How would you find the equation of the line with y-intercept? -$\frac{3}{4}$ and slope -$\frac{1}{2}$?
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1answer
25 views

How does one interpret, geometrically, $\frac{dx}{dt}>0$, $\frac{dx}{dt}<0$ and $\frac{dy}{dt}>0$, $\frac{dy}{dt}<0$?

I'm specifically referring to this example from my lecture notes: I understand, algebraically, what's going on, but what does the fact that, for example, $\frac{dx}{dt}>0$ and ...
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2answers
28 views

Finding the Asymptote / Root of a reciprocal function

$$y = \frac{3}{8x - 3} $$ The y-intercept is $-1$ and the vertical asymptote is $x = \frac{3}{8}$ but what would be the horizontal asymptote and the x-intercept in this case? I am asking this as the ...
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1answer
22 views

Functions (Finding Inverse)

$f(x) = x^2 + 2x$ , domain ${x ≥ 1}$ Question: find the inverse The inverse is $f(x) = 1 + \sqrt(1+x)$ (taking the positive square root only) As $f^{-1}(5) = 2$ and as 2 is an element from the ...
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1answer
12 views

Functions inverse + domain

Question part a): !([http://imgur.com/sKJbFKu]) Answer: !http://imgur.com/jRfeXkW Can anyone explain why the inverse must be the negative square root?
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23 views

How can I visualize the following region

surface $z = xy$ inside the cylinder $x^2 + y^2 = 1$ I took level curves for $z=xy$ when $z=-2, z=-1, z=0, z=1, z=2$, and I got two parallel lines $y=0,x=0$, when $z=0$, and various hyperbolas for ...