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zaricus@yahoo.com


12h
comment Showing that $u(x, \, y) = \ln(x^2 + y^2)$ is harmonic without computing partial derivatives
$\ln z = \ln |z| + i \arg z$.
12h
answered Finding Fourier transform of $\frac{x}{(x^2 + 4)^2}$
Jul
20
comment $\ \sqrt{x+39}-\sqrt{x+7}=4 $
you have $-(x+7)$ on the right instead of $x + 7$
Jul
20
comment A simple complex inequality
which square root are you using here? if $z = i$ then one of the choices makes it incorrect
Jul
20
answered $\ \sqrt{x+39}-\sqrt{x+7}=4 $
Jul
19
answered Inequality question­
Jul
16
awarded  Nice Answer
Jul
16
answered Explaining Infinite Sets and The Fault in Our Stars
Jul
13
answered Showing $\ln(\sin(x))$ is in $L_1$
Jul
13
answered For $x>0$, Prove that $\dfrac{x}{1+x^2}<\tan^{-1}x < x$
Jul
13
comment integration of a series in $x\in(0,1)$
Expand ${1 \over 1- x}$ instead. Then in each term integrate by parts to turn the $\log(x)$ into ${1 \over x}$.
Jul
10
revised Proof that if $a_1=1$ and $a_{n+1}=1+\frac{1}{1+a_n}$
added 84 characters in body
Jul
10
awarded  real-analysis
Jul
10
comment Proof that if $a_1=1$ and $a_{n+1}=1+\frac{1}{1+a_n}$
He did say he showed $1 \leq a_n \leq 2$ already but I agree still that is worth pointing out.
Jul
10
answered Proof that if $a_1=1$ and $a_{n+1}=1+\frac{1}{1+a_n}$
Jul
9
revised When is a limit of products not a product of limits?
added 12 characters in body
Jul
9
answered When is a limit of products not a product of limits?
Jul
9
answered Proving existence of surjective $f:\mathbb{N} \rightarrow A$ implies $A$ is at most countable.
Jul
8
revised Simplify: $\displaystyle\frac{\frac{a}{x}-\frac{a}{y}}{\frac{a}{x}+\frac{a}{y}}$
edited tags
Jul
8
comment Entire function $f$ such that $\lim_{|z| \to \infty} |f(z)|=\infty$
Hint for positive number of zeroes: Look at ${1 \over f}$. Hint for finite number of zeroes: zeroes are isolated.