212 reputation
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visits member for 2 years, 2 months
seen Nov 20 '13 at 16:51

Jul
2
awarded  Curious
May
28
awarded  Yearling
Aug
12
comment Show that if $\lfloor x+a \rfloor$ = $\lfloor x+b \rfloor, \forall x \in \Bbb R$ then $a=b$; is showing that $x+a=x+b$ enough?
Not sure if this is correct...
Jul
21
comment Showing that $A = \{\tan x \mid x \in (-\frac{\pi}{2}, \frac{\pi}{2})\}$ is not bounded, without calculus.
well for every y in R the equation tan x = y has at least a solution in (-pi/2, pi/2), x = arctan y + kpi
Jul
21
comment Showing that $A = \{\tan x \mid x \in (-\frac{\pi}{2}, \frac{\pi}{2})\}$ is not bounded, without calculus.
Well since tan has codomain R and is surjective Im(tan) must be R, How to show that R is the domain of tan...than i dont know
Jul
21
comment Showing that $A = \{\tan x \mid x \in (-\frac{\pi}{2}, \frac{\pi}{2})\}$ is not bounded, without calculus.
I guess Calculus was developed to answer this kind of questions
Jul
21
comment Showing that $A = \{\tan x \mid x \in (-\frac{\pi}{2}, \frac{\pi}{2})\}$ is not bounded, without calculus.
Its six x/cos x
Jul
21
asked Showing that $A = \{\tan x \mid x \in (-\frac{\pi}{2}, \frac{\pi}{2})\}$ is not bounded, without calculus.
Jul
10
accepted Infimum, supremum of a set problems
Jul
10
comment Infimum, supremum of a set problems
god it was so simple, didn't even think about this, thanks.
Jul
10
comment Infimum, supremum of a set problems
yes i do but i am not supposed to use it on this problem, it would be too easy, i am looking for a different solution...
Jul
10
comment Infimum, supremum of a set problems
i tried like this, -1 < x < 1 and 0 <= x^2 < 1 adding them up gives -1 < x^2 + x < 2, so inf A = -1 not sure if it is correct
Jul
10
comment Infimum, supremum of a set problems
Its very annoying when you cant even rely on the solutions in the book, good this website exists!
Jul
10
asked Infimum, supremum of a set problems
May
23
comment Limit of sequence, sequence is formed by the root of an equation.
But i know that one is right. Just i wasn't sure about this part.
May
23
comment Limit of sequence, sequence is formed by the root of an equation.
Well i proved it using one of the consequences of Rolle's theorem
May
23
comment Limit of sequence, sequence is formed by the root of an equation.
because $X_n \in (1, \infty) \ \forall n \ge 2$ and $n \to \infty$
May
23
asked Limit of sequence, sequence is formed by the root of an equation.
May
19
accepted How many functions $f:\{1,2,3,4\}→\{1,2,3,4\}$ satisfy $f(1)=f(4)$?
May
19
comment How many functions $f:\{1,2,3,4\}→\{1,2,3,4\}$ satisfy $f(1)=f(4)$?
listing them helped me figuri it out thank you