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5:05 AM
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Q: Problem on differential equation.

VegaQ: $f\left(x\right)$ is a continuous and differentiable function defined in $[0,\infty)$. If $f\left(0\right)=1$ and $f'\left(x\right)>3f\left(x\right)\ $ $∀\ x\ \ge0$ then prove that $f\left(x\right)\ge e^{3x}\ ∀\ x\ \ge0$ Approach: Given $$f'\left(x\right)>3f\left(x\right)\ $$ Let $f\left(x\...

There are two older occurrences of - both of them from the sam user and both of them about Brocard's problem.
One possible problem I can see with a tag called is that - similarly as for - some users might use it for any question containing some problem. In the same spirit, many users use for any question related to some proof.
 
 
17 hours later…
10:36 PM
A new tag was created.
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Q: Inverse image of $Y$ and cardinality.

intheshadowI need to solve the following exercise. Let $X$ be a non empty set and $P_2$ the set whose elements are all the subsets of $X$ that have $1$ or $2$ elements. We have $f$ : $f : X^2 \rightarrow P2$ $(x, y) \mapsto \{x, y\}$ Let $Y\in{P2}$. Determine $f^{-1}(\left\{{Y}\right\})$ and find its cardin...

Mar 4 at 2:15, by Martin Sleziak
There is a new tag called . This tag (and once also ) were added and removed also in other questions: https://math.stackexchange.com/posts/4047897/revisions https://math.stackexchange.com/posts/4046166/revisions https://math.stackexchange.com/posts/4046189/revisions
Mar 4 at 2:18, by Martin Sleziak
Posts where the tag was added/removed (including the editors): https://data.stackexchange.com/math/query/1105163/questions-which-had-the-given-tag-including-the-editor-who-added-it?tagname=domain https://data.stackexchange.com/math/query/1038474/questions-which-no-longer-have-the-given-tag-including-the-editor?tagName=domain
 

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