# Tagged Questions

190 views

### Problems with fake proofs of limit of sequences

I can hardly imagine an easier example of the fact that my understanding of the topic is more than rusty. I will divide the question in two parts to make the reading easier: 1) Background; 2) ...
159 views

### Solve for $x$: $\frac{\sqrt{x}}{2} = -1$

I recently saw in the Thread on Mathematical Misconceptions a post which implied that the following equation has no known solutions: $$\frac{\sqrt{x}}{2} = -1$$ Why does this not have any solutions? ...
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### What's wrong with my method that gives $0.\bar9 = 1$? [duplicate]

This is what I learned : $x = 0.\bar3$ (I) $10x=3.\bar3$ (II) (II)-(I) : $9x = 3 => x = 1/3.$ And It's OK. But now, I think this similar calculation gives me wrong answer: $x = 0.\bar9$ ...
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### Asymptote of a line?

If a rational function is defined as $f(x) = \frac{p(x)} {q(x)}$ for any two polynomials $p(x)$ and $q(x)$; given $p(x) = 2x+1$ (polynomial of degree 1) and $q(x) = 3$ (polynomial of degree zero), and ...
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### What step is wrong? [duplicate]

Possible Duplicate: Finding the error in a proof $a=b$ $ab=a^2$ $ab-b^2=a^2-b^2$ $b(a-b)=(a+b)(a-b)$ $b= a+b$ Reminder the first step where $b = 2b$ So, $1=2$ In this case in my ...
806 views

### why 0=0 is not possible??

Hi one of my friend showed me one proof i.e. $1)$ $2^2 - 2^2 = 10 - 10$ $2)$ $(2+2) (2-2) = 5 (2-2)$ $3)$ dividing both sides by (2-2) $4)$ $(2 + 2) = 5$ I know this is wrong in first line as ...
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2k views

### How to explain what is wrong in this?

My friend showed this to me and I instantly know that this is wrong. However, I cannot explain why this is wrong to my friend. Question. Prove $\displaystyle \frac{100-100}{100-100} = 2.$ ...
262 views

### How to explain this $3=2$ proof? [duplicate]

Possible Duplicate: The $3 = 2$ trick on Google+ I saw google some links http://www.astahost.com/info/tiiiss-ramanujams-proof-flaws.html $$-6 = -6$$ $$9-15 = 4-10$$ adding ...
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### Is $(x+1)^2 = (x+1)^3$ for any $x$?

This is something I've been struggling to understand since the past few days. Let's take an example: Prove/Disprove: $(x+1)^2 = (x+1)^3$ for all real values of $x$. Proof: Let us assume the ...
### $i^2$ why is it $-1$ when you can show it is $1$?
We know $$i^2=-1$$then why does this happen? $$i^2 = \sqrt{-1}\times\sqrt{-1}$$ $$=\sqrt{-1\times-1}$$ $$=\sqrt{1}$$ $$= 1$$ EDIT: I see this has been dealt with before but at least with ...