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1d
answered How to prove $f(x)=\sqrt{x+2\sqrt{2x-4}}+\sqrt{x-2\sqrt{2x-4}}$ is not differentiable at $x=4$?
2d
revised Proving that a function is Riemann Integrable
added 17 characters in body
Jul
27
comment Proof that |x-a| is continuous at x=a (epsilon delta), and nondifferentiable at x=a.
@Charles I have updated my answer, now it should be complete.
Jul
27
revised Proof that |x-a| is continuous at x=a (epsilon delta), and nondifferentiable at x=a.
added 608 characters in body
Jul
27
revised show this sequence inequality $x_{2^n}$
added 6 characters in body
Jul
26
answered Proof that |x-a| is continuous at x=a (epsilon delta), and nondifferentiable at x=a.
Jul
26
comment Why there is no sign of logic symbols in mathematical texts?
@ThomasAndrews Here in Italy most classical books in mathematics used to be written in a very literary way. I know that english is a more straightforward language if compared to latin languages... My books were full of sentences like "Fissiamo arbitrariamente un numero $\epsilon>0$" (Let us arbitrarily fix a number $\epsilon>0$)!
Jul
26
revised How to integrate $\int \frac{e^x \cos x}{\tan x+\operatorname{sec}x}dx$?
added 19 characters in body; edited title
Jul
26
comment Exploit uniform continuity
What about $\epsilon^*$ as a function of $\epsilon$? Do you allow it to be unbounded as $\epsilon \to 0$?
Jul
26
answered Reference for differentiation of an integral over variable ball
Jul
26
comment why at saddle point is second derivative 0?
You will discover the answer by carefully studying the definitions and theorems in your book on advanced calculus in several variables.
Jul
26
revised Infinite determinant
added 18 characters in body
Jul
25
answered Spivak's 'Calculus', 5-21(b): Is there an easier/shorter way?
Jul
25
comment $\int_0^b \ln(\sin(ax))dx$
@Zach466920 Well, I do.
Jul
25
revised Signum function question
added 29 characters in body
Jul
25
reviewed Close differentiation
Jul
25
reviewed Close How to prove: Union of a chain of well-ordered sets w.r.t continuation is well ordered
Jul
25
comment $\int_0^b \ln(\sin(ax))dx$
@Zach466920 I could not find any proof in that thread, just a closed formula obtained by some obscure technique. I would not say that the answer is contained in that thread.
Jul
25
comment $\int_0^b \ln(\sin(ax))dx$
A primitive can be found in terms of complex special functions: wolframalpha.com/input/…
Jul
25
comment Prove that the linear transformations are the same.
@user119615 Thank you, my fault!