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visits member for 3 years, 10 months
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Jun
14
comment Is composition of analytic functions itself analytic?
This requires first the proof that any differentiable complex function is analytic, which I think is a non-trivial theorem. Anyway, what about real analysis? Can this be proven without complex numbers?
Jun
14
comment Is composition of analytic functions itself analytic?
@Giuseppe Negro and what? these problems do not make it non-analytic and non-holomorphic.
Jun
13
comment What is $\tan50^\circ$
@David H haha, very funny
Jun
13
comment What is $\tan50^\circ$
1.19175 is not the exact value.
May
27
comment What makes elementary functions elementary?
|x| is not an elementary function.
Apr
18
comment Maximum among $1, 2^{1/2}, 3^{1/3}, 4^{1/4},…$
what do you mean by "greatest absolute value from"?
Apr
18
comment Maximum among $1, 2^{1/2}, 3^{1/3}, 4^{1/4},…$
The closest number is not necessary the greater.
Apr
18
comment Whats an extended complex plane?
@Daniel Fischer mathworld.wolfram.com/ExtendedComplexPlane.html
Apr
17
comment Is the theory of dual numbers strong enough to develop real analysis, and does it resemble Newton's historical method for doing calculus?
@Mike Battaglia maybe it causes problems with distributiveness of multiplication? $0/0=\epsilon^2 \omega^2=(\epsilon\omega)(\epsilon\omega)=1$.
Apr
15
comment Where to find reference about dealing with operators in form of formal power series?
@Michael Hardy in $(D/D)f$ do you mean multiplication or application of operator? I used square brackets to indicate application of operator to a function.
Mar
24
comment Is there a special name for pi-based finite difference?
@nik no, check yourself. Pi is the period of tangent.
Mar
24
comment How to define the $0^0$?
The second premise is wrong.
Mar
17
comment What is the arithmetic mean of all positive integers less than $1$?
@robjohn no. wrong.
Mar
17
comment What is the arithmetic mean of all positive integers less than $1$?
@robjohn what the question is what the answer. If the question has any meaning at all, the answer is 1/2.
Mar
5
comment What is series coefficient for $f(x)=\csc^2 x - \frac1{x^2}$?
it seemed to me that your answer was not finished because it ended with a comma.
Mar
5
comment What is series coefficient for $f(x)=\csc^2 x - \frac1{x^2}$?
I already found the answer to this question: math.stackexchange.com/questions/699611/…
Mar
5
comment Why this function is elementary and its pair is not?
@vonbrand the first one is $\csc^2 x - \frac1{x^2}$, the second one can only be explained using polygamma or Hurwitz zeta.
Mar
5
comment Zero to the zero power - Is $0^0=1$?
One does not exclude the other, this can be both indeterminate form when considering limits, AND defined.
Mar
4
comment Given an even function how to obtain the most close odd function and vise versa?
@user86418 tanh(nx) is not discrete-analytic for large enough n, see here for a similar case: mathoverflow.net/questions/99166/…
Mar
4
comment Given an even function how to obtain the most close odd function and vise versa?
@user86418 thanks, I have addressed this.