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In example 1 an error is made on line 3

1/((2n-1)(2n+1)) = 1/(4n+2) - 1/(4n-2)

this is not correct, the correct answer is.

1/((2n-1)(2n+1)) = 1/(4n-2) - 1/(4n+2)

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Superbugger 16 Jun 2018 00:29

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

In example 1 an error is made on line 3

1/((2n-1)(2n+1)) = 1/(4n+2) - 1/(4n-2)

this is not correct, the correct answer is.

1/((2n-1)(2n+1)) = 1/(4n-2) - 1/(4n+2)

filosophreak 13 Jun 2018 14:11

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

"Let ϵ>0 be given and let δϵ=ϵL. Then for all x,y∈A such that ∣x−y∣<δϵ=ϵL

then ∣f(x)−f(y)∣≤L∣x−y∣=Lδϵ=L⋅ϵL=ϵ, and so f is uniformly continuous on A. ■"

Second line should be ∣f(x)−f(y)∣≤L∣x−y∣ *<* Lδϵ=L⋅ϵL=ϵ (change from equals to strictly less)

steph1220 (guest) 12 Jun 2018 10:21

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

In the Article "Equivalence of Norms in a Finite-Dimensional Linear Space" there seems to be an error with the definition of the function f in (11). I think it should be

(1)\begin{align} \quad f(x_1, x_2, ..., x_n) =\biggr \| \sum_{k=1}^{n} x_ke_k \biggr \| \end{align}

with x's instead of a's.

MathOnline 06 Jun 2018 05:34

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Thanks for catching this! It has since been fixed :D.

MathOnline 04 Jun 2018 20:23

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Thank you for catching this typo! It has been corrected!

MathOnline 04 Jun 2018 20:22

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Thank you for finding this! It has since been corrected!

MathOnline 04 Jun 2018 20:20

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Thank you for catching this! I have fixed it!

MathOnline 04 Jun 2018 20:17

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

I have just added some references! I had been meaning to do this for awhile. Thanks for reminding me!

MathOnline 04 Jun 2018 20:13

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

This should be fixed now! Thank you for finding this!

Zim (guest) 19 May 2018 16:04

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

On the page The Implicit Function Theorem, "is defined is defined" should only be "is defined" in the following line:

Suppose that y=f(x) is a single variable real-valued function that is defined is defined implicitly such that F(x,y)=F(x,y(x))=0, and suppose that the point (a,b) lies on this curve (and so F(a,b)=0).

Zeekless (guest) 15 May 2018 09:12

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

On the page "List of List of Fundamental Groups of Common Spaces"

Section: "Fundamental Groups of Less Common Spaces"

Space: The Torus Minus a Point

The mistake is that the fundamental group is written to be ZxZ, while it is actually F2 (free group with 2 generators). Note that in "The Reasoning" the group is mentioned correctly.

Vincent (guest) 20 Mar 2018 13:18

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

The Jacobian Matrix of Differentiable Functions from Rn to Rm article of real analysis

Jacobin of line (5)

Naoaki (guest) 15 Mar 2018 06:58

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

name: the-ring-of-z-2z

error: the table 2 is not obey the rule that even * even = even, even * odd = even, odd * even = even, and odd * odd = odd.

Anthony (guest) 08 Mar 2018 17:51

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Not really a bug, but more of a quality of life update that I would like to see on the wikidot. I want to know what books you used to create each subsection. Keep up the great work! :D

Nathan Ha 02 Mar 2018 13:13

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

In (2), shouldn't we have

alpha is homotopic to alpha', relative to {0,1}, and

beta is homotopic to beta', relative to {0,1}

?

Gamma Sigma 23 Feb 2018 14:50

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

We did not specify any restrictions on x or y, and so the domain is

(1)\begin{align} D(f)=\{(x,y)∈\mathbb{R}^2:x,y∈\mathbb{R}\}=\mathbb{R}^2 \end{align}

Furthermore, we know that the plane

(2)\begin{equation} z=x+y \end{equation}

has a normal vector

(3)\begin{align} \vec{n}=(1,1,−1) \end{align}

and so this plane is not parallel to the xy-plane, and so

(4)\begin{align} R(f)=\mathbb{R}^2 \end{align}

But, since we are talking about a two-variable input and a real, scalar (single number) output, shouldn't the Range be

(5)\begin{align} R(f)=\mathbb{R} \end{align}

?

Gamma Sigma 23 Feb 2018 14:34

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Example 5:

Similar to example 4 that I have just posted; the page says the Domain is:

(1)\begin{align} D(f)=\{(x,y):y≥x \wedge y≠x^2\} \end{align}

Shouldn't the Domain be:

(2)\begin{align} D(f)=\{(x,y):y≥-x \wedge y≠x^2\} \end{align}

instead?

(Negative sign on x)

Gamma Sigma 23 Feb 2018 14:22

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

Example 4:

Determine and illustrate the domain of the function

(1)\begin{equation} f(x,y)=ln(x+y) \end{equation}

We note that

(2)\begin{equation} x+y>0 \end{equation}

and so the domain of f contains all points

(3)\begin{equation} (x,y) \end{equation}

such that

(4)\begin{equation} y>x \end{equation}

in other words

(5)\begin{align} D(f)=\{(x,y):y>x\} \end{align}

as depicted.

But shouldn't it be:

(6)\begin{align} D(f)=\{(x,y):y>-x\} \end{align}

?

Guest (guest) 23 Feb 2018 07:07

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

On the page "Biology Application - Population Growth Curves" in the Calculus section, there is a discrepancy in the population functions. In all cases, the function is notated as P(t) and P'(t), but both the function itself and the derivative operator are in terms of x (e.g. d/dx instead of d/dt and (-10000/x+20) vs (-10000/t+20). When finding out P'(100) when t = 100, 100 is plugged in for x instead. This could be cleared up by changing all of the x's to t's.

Keep up the good work here!

MathOnline 18 Feb 2018 03:45

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

in discussion Hidden / Per page discussions » Submitting an Error on Math Online

**Thank you everyone for posting errors! I have tried to fix (most) of them!**

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