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Jan
12
comment Is there an intuitive explanation for $ x^2+y^2=7 z^2 $ doesn't have any integer solution?
I still I can't see where you use the fact that $x^2+y^2=z^2$ has infinite integer solutions.
Jan
12
comment Is there an intuitive explanation for $ x^2+y^2=7 z^2 $ doesn't have any integer solution?
That is neither a answer to the question ("Does this fact ...") nor does this give us a complete answer to the more usefull question: what are the integer solutions of the equation.
Jan
11
awarded  Announcer
Jan
10
comment how can I prove that $\frac{\arctan x}{x }< 1$?
@enzolib: thanks, I added this to the answer.
Jan
10
revised how can I prove that $\frac{\arctan x}{x }< 1$?
incorporated the comment of @enzolib
Jan
10
revised how can I prove that $\frac{\arctan x}{x }< 1$?
added 223 characters in body
Jan
10
answered how can I prove that $\frac{\arctan x}{x }< 1$?
Jan
9
comment How do I find which set of functions is linearly independent?
and how do you prove that all other are not linear dependent?
Jan
9
revised How do I find which set of functions is linearly independent?
deleted 1 character in body; edited title
Jan
9
reviewed Approve How do I find which set of functions is linearly independent?
Jan
7
reviewed Approve Is time a continuous random variable?
Jan
6
reviewed Approve Solving a differential equation using Laplace transform?
Jan
6
reviewed Reject Expected value of a die when decision to role again depends on previous outcome
Jan
5
answered Better way of factorising $x^2-a^2+x+a$
Jan
5
comment Better way of factorising $x^2-a^2+x+a$
here is a more systematic technic math.stackexchange.com/a/544042/11206 but maybe much more than you want.
Jan
5
comment Better way of factorising $x^2-a^2+x+a$
+1, but maybe incomprehensibly to the OP
Jan
5
comment Better way of factorising $x^2-a^2+x+a$
$x({1^2}+1)-a(1^2-1)$ equals $2x$ and not ${x^2}-{a^2}+x+a$. As Hurkyl already noted, your attempt to create a common factor contains an error.
Jan
5
reviewed Reject Give an example of a nonempty finite set which is neither open nor closed?
Jan
5
revised Find least possible number of factors
added 12 characters in body
Jan
5
comment Find least possible number of factors
Where can I see that this is a multiple choice question?