Feb
22
comment An equation, where the solution does not exist, but on solving the equation we got a solution. why this is happening?
process your solution procedure in reverse order: substitute your solution for x in the equation. when it first hapens that it is not a solution then figure out what happened
Feb
19
comment $\angle ABD=38°, \angle DBC=46°, \angle BCA=22°, \angle ACD=48°,$ then find $\angle BDA$
Is there a precise definition for elementary geometry? Congruent triangle , compass and ruler constructions, what else?
Feb
19
revised $f(f(x))=f(x)$ question
formatting
Feb
19
revised $f(f(x))=f(x)$ question
formatting
Feb
19
revised $f(f(x))=f(x)$ question
added 35 characters in body
Feb
19
comment $f(f(x))=f(x)$ question
@fatmattxle yes
Feb
19
answered $f(f(x))=f(x)$ question
Feb
19
comment $f(f(x))=f(x)$ question
$f(x)=0,x \in \mathbb{Q}$, else $f(x)=\pi$. is a function that is not continous and has this property
Feb
19
comment $f(f(x))=f(x)$ question
Combine some of these three: $f(x)=x,x>0$, $f(x)=const, x<0$
Feb
19
answered Find sum of roots of complex equation $z^6 = z^{18} = -1$
Feb
17
answered Relation betwen coefficients and roots of a polynomial, K.A.Stroud
Feb
17
comment Grandi's series contradiction
no, it is not a contradicition. closed under addition means that any finite sum of integer is an integer. Are you talking about finite sums of integers? What are you talking about? It is a contradiction of you say $S=0$ and $S=1$ because the numbers $0$ and $1$ are different in $\mathbb{Z}$
Feb
17
comment Regions in $\mathbb{C}$ containing rectangles
@5xum No, if $\Omega$ is the rectangle $1,i,-1,-1$ an the right triangle is $0.9, 0, 0.9i$ the 4th vertex is $0.9+0.9i$ which is not in $\Omega$
Feb
17
comment Regions in $\mathbb{C}$ containing rectangles
@Marcin Łoś No, if $\Omega$ is the rectangle $1,i,-1,-1$ an the right triangle is $0.9, 0, 0.9i$ the 4th vertex is $0.9+0.9i$ which is not in $\Omega$
Feb
17
comment Regions in $\mathbb{C}$ containing rectangles
So it is not necessary for $\Omega$ to be connected?
Feb
16
comment probability $2/4$ vs $3/6$
@Thomas Ahle is the question unintuitive or the answer?
Feb
16
comment Tricks. If $\{x_n\}$ converges, then Cesaro Mean converges (S.A. pp 50 2.3.11)
What is the meaning of S.A. int the title?
Feb
16
comment Tricky positive diophantine equation
Where have you found this problem?
Feb
14
comment Non-zero prime ideals of $F[x]$ are maximal
all posters have questions about something. something like "ideals of $F[X]$" would be a more meaningful title
Feb
13
comment Finding the zeros of a polynomial equation.
here an example of calculationg the root with Cardanos formula. But this is rather labourious. Maybe there is a typo in the equation? You can find the exact solution using a CAS like Wolfram Alpha.