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

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2answers
29 views

Need help to understand a math task about algebraic and parametric equations

Can anybody please explain this for me?: Find the algebraic and parametric equations of the circle with centre (-2,3) that passes through (1,-1) How do I find the algebraic and parametric ...
1
vote
1answer
20 views

Identifying the formula for a quartic graphic

I am attempting to help someone with their homework and these concepts are a bit above me. I apologize for the terrible graph drawing. I am using a surface pro 3 and it has an awful camera so I can't ...
4
votes
1answer
2k views

Linear Programming: Three variable graphical solution

A small bank offers three type of loans: housing loans at $8.50$% interest, education loans at $13.75$% interest rates, and loans to senior citizens at $12.25$% interest. Further, it needs to ...
0
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4answers
51 views

Tool to draw graphs when input points are given

I am writing a dissertation and I have a two collections of data from my research which I would like to compare using graphs. I have the values for abscissa and ordinate and I am looking for some sort ...
2
votes
2answers
49 views

Sketch the complex function: $z\overline{z}+(1+2i)z+(1-2i)+1=0$

Tried sketching the complex function: $z\overline{z}+(1+2i)z+(1-2i)+1=0$ I first simplified it by converting $z=x+yi$ I got: $(x+yi)(x-yi)+(1+2i)(x+yi)+(1-2i)+1=0$ Which gave me this implicit ...
2
votes
1answer
694 views

Plotting power-law fit in cumulative distribution function plots

In "Power-law Distributions in Empirical Data", the authors give several examples of alleged power-laws. For instance, they plot node degree distribution of the Internet like this (p. 24): where ...
0
votes
0answers
13 views

What's the best open source software for converting plots into Math functions?

I need to complete a year 12 Math homework which involves choosing an object with axial symmetry, plotting its side view on a piece of paper, integrating the resulting curve (assuming a 3D object is ...
0
votes
1answer
348 views

New definition for triangle wave?

There's always a huge formula for the triangle wave, or the "teeth" function as I like to call it. Shouldn't this give a teeth function too? It's sorta hard to understand, but once you get the hang of ...
3
votes
3answers
61 views

Geometric interpretation of inverse complex function?

Function $f\colon\mathbb{R}\to\mathbb{R}$ and its inverse $f^{-1}$ are symmetric over line $y=x$. It's easy to imagine inverse of real function, we just have to "flip" the plot over $y=x$. But what ...
2
votes
2answers
61 views

Vector Functions of One Variable

Question A particle moves along the curve of the intersection of the cylinders $y=-x^2$ and $z=x^2$ in the direction in which $x$ increases. (All distances are in cm.) At the instant when the ...
1
vote
1answer
295 views

Intersection of a point and absolute value function contained within a circle

I'm attempting some crazy ideas while programming a game and ran into the following math problem that has been bugging me for a few days: Given a unit circle and a random point $P$ within the circle, ...
0
votes
1answer
32 views

How do I solve this limit

**Find the limit ${x \to 6}$ if $ f(f(x))$ ** Any idea how to solve this graphical question on limits?
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0answers
23 views

graph of a function [closed]

Graph the equation $$y=x^3+4x^2-5x-20$$ Use the window $X: -5,5,1$, $Y: -30,30,5$ Find the domain and range. Find the $x$ and $y$ intercepts and write as ordered pair. ...
1
vote
1answer
22 views

Sketching a Graph of a Particle Trajectory

How can I sketch the trajectory of a particle of mass $m$ with a position vector $\mathbf{r} = \cos(\omega t)\,\hat{\mathbf{i}} + \sin(3\omega t)\,\hat{\mathbf{j}}$ ? Will this be a three ...
1
vote
0answers
56 views

Does anyone recognize this graph?

It's a plot of the following: Let $$f_{(n)} = \frac{np_n}{(p_1 + \ldots + p_n)}$$ so that $$g_{(n)} = \left|\space f_{(n)} - f_{(n-k)}\right| $$ where $n > k$ and $k = 5$ in this example. For ...
0
votes
2answers
78 views

How to get polynom formula from drawing?

I would like to have an analytic formula for certain functions that I can draw with a pen. For example, if I want a function like that then I can model it with the function $$ V(x) = (x-a)^2 ...
0
votes
2answers
59 views

How can I compress outliers more than the middle values in a chart?

I have a voting contest and am displaying a chart of votes. To keep from discouraging voters who would be interested in voting for non-winning options, I want to compress the differences between ...
2
votes
1answer
27 views

Confusion with Heaviside Step Function and Ramp Function.

I want to know how to represent the following graph with Heaviside step functions and ramp functions. My guess is that this is represented as $r(t) -r(t-2) +2u(t-2)$, where $r(t)$ is the unit ramp ...
0
votes
2answers
42 views

reflecting a function about a line

Say you have a function $f(x)$ and a line $g(x)=ax+b$. How do you reflect $f$ about $g$? I am apparently supposed to write more text, but the line above is all I am after, hence I wrote this sentence ...
0
votes
1answer
16 views

Plotting a convex optimization problem

I have an optimization problem like below: $\text{minimize } - \sum_k w_k \log r_k$ $ a \leq r_k \leq b_k, k = 1, \cdots, 10$ Here, $w $ and $b$ is a set of constant: $w = [w_1, \cdots, w_{10}]$ ...
0
votes
1answer
32 views

When does function $(\log_b(x))^p$ change its curvature?

Consider $(\log_b(x))^p$ where $b$ is a constant $>1$; $x, p \in \mathbb R_+$. As we increase the value of $p$ (starting from 1), at specific value of $p$, the curve changes its shape from ...
0
votes
1answer
10 views

Comparing a function and its estimate

What are some clever ways of comparing (visually) a function with its estimate? For regions where the function does not cross zero, plotting the ratio of the functions and plotting the relative error ...
-2
votes
2answers
31 views

specifying an asymptotic function

Please help me out; I need to specify a function satisfying these conditions: $$ f(0)=1 \;\;;\;\lim_{x \to \infty}f(x)=0$$ Hopefully does there exist a simple answer? Thanks a lot!
0
votes
2answers
28 views

drawing square root of an unknown function with a double root.

Without the equation of the function $y=f(x)$ and only the diagram, how would you draw $y=\sqrt{f(x)}$ and why? I am most interested in root if it looks like a double root but not necessarily a ...
3
votes
0answers
14 views

How does emergent oscillation appear in this animation of concentric circles?

I made this animation and I barely understand it. http://bl.ocks.org/tophtucker/500d2a010105cfcc87db It's a bunch of concentric circles with exclusion compositing. The radius of the ...
0
votes
0answers
19 views

Let T be the resultant BFS tree. If (u,v) is an edge of G that is not in T, then which one of the following CANNOT be the value of d(u)−d(v)?

This is MCQ of a competitive exam (GATE) , answer is option (d) given by GATE . I found explanation for (d) . With the commonsense or guessing the will be option (d) generally , I have doubt "Is given ...
-3
votes
1answer
19 views

Scale Proportionally a Polynomial [closed]

I have 3 polynomial functions that all overlap (to form a shape): I need to scale the polynomials down to half the current size. How do I do this? It must be scaled down proportionally ($x$ and ...
1
vote
1answer
60 views

Converting $x^y-y^x=1$ Into $y=$ Form

This is probably going to be a simple answer, but, how would you convert $x^y-y^x=1$ into $y=$ form without any $y$ on the opposite side of the equation?
0
votes
0answers
33 views

What is this curve?

A quick question. I have the following plot: Just looking at the coloured band where it transitions from red to blue, it looks like a function I have seen somewhere before (rotated 90deg ...
1
vote
2answers
48 views

Is the function $\ln(ax + b)$ increasing/decreasing, concave/convex?

$h(x) = \ln(ax + b)$ NB. Examine your results acccording to values of $(a,b)$ I've differentiated twice in order to get the following: $$ h''(x) = -\frac{a^2}{(ax+b)^2} $$ I think this proves ...
1
vote
1answer
50 views

Is the count for graphing trigonometric functions always 1/4 of a period? [closed]

I saw this video in YouTube since I'm studying for a quiz and found out that the count used for graphing trigonometric functions is 1/4 of a period. Is it always like that?? Sine, cosine, tangent, ...
-1
votes
1answer
31 views

How would I plot this function for all values of X,Y? [closed]

I have this function which I wish to plot: $y=b(a-x)^{8/25}$ I have the values for $x,y$ as part of a data set, with thousands of values. This is in a file. What i have found is that $x$ is between ...
2
votes
2answers
36 views

$6x -3y -18 =0$ What does $x$ and $y$ equal on a straight line graph?

I need to sketch a graph of $6x-3y-18=0$. I don't know if I'm on the right track but this is what I tried to get $x$: $6x-3y-18=0$ $\Rightarrow 6x-3y+18=0+18$ $\Rightarrow 6x-3y=18$ $\Rightarrow ...
-2
votes
1answer
21 views

Finding the horizontal asymptotes of a function

Here is the function I am trying to find the horizontal asymptotes for: $y=\frac{1-2^x}{1+2^x}$ Could you please explain how the horizontal asymptotes can be found for this function? Thanks.
0
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3answers
27 views

If the coefficients of the y-terms are equal and the coefficients of the x-terms are equal, the graphs of the two lines will be parallel.

So a student has a claim that for any pair of linear relations, if the coefficients of the y-terms are equal and the coefficients of the x-terms are equal, the graphs of the two lines will be ...
0
votes
2answers
59 views

Abnormal graph curve explanation? Exponential?

I am conducting research on a plot of data. Most appear linear, as expected, but one series was different. The dark red plot (below) is a more accelerated growth curve - and I'm wondering why? Here ...
0
votes
0answers
19 views

Plot zeroes of polyomial in $\mathbb{R}[x,y,z]$ in Linux

I have a polynomial in $\mathbb{R}[x,y,z]$, say $$p_c(x,y,z)=x^2+y^2+z^2-xyz-c.$$ Do you know any simple piece of software to plot the zeroes of this polynomial using Linux? In the past I plotted ...
0
votes
0answers
29 views

Functon fitting goes wrong

Let's say I got a some function (let's say it named $B_w$) and I make a curve deped on some parameters. As example ...
3
votes
1answer
385 views

Plotting discrete time signals involving sumations in matlab.

Many of the examples I've encountered while looking for an answer are simple functions that do not involve summations. Suppose I have the following function; ...
0
votes
2answers
44 views

Write a linear equation that represents this scenario.

Emma is planning her summer and would like to work enough to travel and buy a new laptop. She can earn 90 dollars each day, after deductions, and she can work a maximum of 40 days in July and August, ...
0
votes
1answer
358 views

What is a moving average system?

Can someone elaborate on what a moving average system is? I know that the system is defined as: $$y[n] = \frac{x[n] + x[n-1] + x[n-2]}{3}$$ How would we draw $y[n]$ given that we have a graph with ...
1
vote
0answers
13 views

parsimonious definition of a zig-zag function between two bounds

Suppose I have some strictly increasing function $f:[0,b]\to[0,b]$ with $0<b<1$, $f(x)<x$ and $f'(b)=\frac{1-f(b)}{1-b}$ (i.e. tangent to the secant line to $(1,1)$). Now imagine a 'tunnel' ...
0
votes
2answers
78 views

How to sketch level curves/sections?

I am asked to sketch the level curves and sections of $z = xy$. So first I sketch some level curves by setting $xy=c$ and I get a bunch of curves in all the quadrants (I know what $y=\frac{1}{x}$ ...
1
vote
3answers
61 views

How to sketch a surface in a three-dimensional space?

I was asked to hand sketch the surface defined by $$x^2+y^2-z^2=1$$ How could I do that? I find it particularly hard to draw graph in three-dimension, could you give me some advice?
1
vote
1answer
36 views

$\sin^{-1}(\frac{2x}{1+x^2})+px=0$ has exactly 3 solution

If the set of values of $p$ for which the equation $\sin^{-1}(\frac{2x}{1+x^2})+px=0$ has exactly 3 solution is $(l,m)$.Then what is $2m-l$? ...
2
votes
1answer
28 views

Is there a better way to represent the following formula?

A student has developed a money-saving strategy that uses the formula S = 450 + 100r . a) Give a possible interpretation of his strategy. I don't really know if my initial interpretation really ...
4
votes
2answers
64 views

Why is there a discontinuity at zero?

For the function $$y = \frac{2x^2}{x-3},$$ I understand that $x = 3$ and $y = 2x+6$ are asymptote, but according to the answers in my textbook, there is a discontinuity at the origin. Why is this?
1
vote
1answer
35 views

Determine the domain and range of the following relations using set builder notation.

I think I am starting to get the hang of using set builder notation, but I'm getting confused with the end points of these two specific questions. The blue text is hat I have already, but it would ...
1
vote
1answer
17 views

Drawing ellipsoid with tanh

The function $f(x,y)=\tanh(R-\sqrt{x^2+y^2})$ for a given $R>0$ draws a circle with radius R with maximum and minimum of +1 and -1. This I can see when I plot ...
0
votes
0answers
19 views

How to find the formula of a function from its graph?

I've got some data points (X/Y coordinates) that were apparently created using a certain formula that I want to reconstruct now. I've only got those points, and I can plot them (e.g. like in this). I ...