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21h
answered Calculate point coordinates from other points
1d
answered arithmetic mean of smallest numbers of all subsets of r elements formed out of (1,2,..n)
2d
revised Poisson distribution- mosquitos question
fix typo
2d
answered Poisson distribution- mosquitos question
2d
comment Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$
Doh! Sorry about that.
2d
revised Contour Integral of $\int\limits_0^{2\pi}\frac{d\theta}{1+a\cos\theta}$ for $a^2<1$ (textbook wrong?)
add a real method verification
2d
comment Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$
Related to cosh x inequality - Mathematics Stack Exchange:
2d
revised Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$
fix typo
2d
answered Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$
2d
answered Contour Integral of $\int\limits_0^{2\pi}\frac{d\theta}{1+a\cos\theta}$ for $a^2<1$ (textbook wrong?)
Apr
25
comment Normal system of the least square method
I thought you were wondering why the factor of $2$ was not in the derivative of $\|Pa-y\|$. I didn't think you were concerned about the factor of $2$ in $2P^T(Pa-y)=0$ since $2x=0\iff x=0$. What is it that is bothering you about the factor of $2$?
Apr
25
comment Normal system of the least square method
@MarcZ: If the addendum does not answer your question, let me know.
Apr
25
revised Normal system of the least square method
add some about the derivative of the norm
Apr
25
revised Normal system of the least square method
not necessarily a square matrix
Apr
25
answered Normal system of the least square method
Apr
24
revised How do I show that $\sum_{i = 1}^n \frac 1{\sqrt{a_n}} \lt \frac {\sqrt 3}6$ for $a_n = 4n(4n + 1)(4n + 2)$?
add motivation
Apr
24
comment How do I show that $\sum_{i = 1}^n \frac 1{\sqrt{a_n}} \lt \frac {\sqrt 3}6$ for $a_n = 4n(4n + 1)(4n + 2)$?
I just realized that this is the same as Jack's answer, so I have added my motivation.
Apr
24
answered How do I show that $\sum_{i = 1}^n \frac 1{\sqrt{a_n}} \lt \frac {\sqrt 3}6$ for $a_n = 4n(4n + 1)(4n + 2)$?
Apr
24
comment Derivative of $\arctan y $
Please don't delete your question as soon as someone answers. This is not fair to the person who has answered your question.
Apr
24
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