news
How does the wheel paradox work?
I keep looking at this picture and its driving me crazy. How can the smaller circle travel the same distance when its circumference is less than the entir...
Apr 18, 2026
Archive: News
news
Worst case analysis of MAX-HEAPIFY procedure .
From CLRS book for MAX-HEAPIFY procedure : The children's subtrees each have size at most 2n/3 - the worst case occurs when the last row of the tree ...
Apr 18, 2026
news
what is "log-average"?
It was mentioned in pLSA paper that perplexity refers to the log-averaged inverse probability on unseen data. Can any one give me the exact formula for ca...
Apr 18, 2026
news
Calculate $\pi$ to an accuracy of 5 decimal places?
In this message at point 18 I saw following programming question: Given that $\pi$ can be estimated using the function $4(1 – 1/3 + 1/5 – 1/7 + \ldots)$ w...
Apr 18, 2026
![Square root of a squared number: $\sqrt{a^2} = a \in \mathbb R$? [duplicate]](https://news.conceivablytech.com/uploads/square-root-of-a-squared-number-sqrt-a-2-a-in-mathbb-r-duplicate_720.jpg)
news
Square root of a squared number: $\sqrt{a^2} = a \in \mathbb R$? [duplicate]
True or False $$a\in \mathbb R\implies \sqrt{a^2} = a$$ a positive or negative, will always be equal to a, so for me it is true, but the teacher says that...
Apr 18, 2026
news
Method of coding to find the mean and standard deviation
The mass of each of 300 packets of flour produced by a factory in labelled 1kg. When the mass of each packet is measured to the nearest $0.001$ kg, the fo...
Apr 18, 2026
news
Difference between multiplication, dot product, and cross product symbols
What is the difference between the symbols for multiplication, dot product, and cross product symbols? How can we tell them apart?
Apr 18, 2026
news
How do I use the Tableau Method?
I have to do different exercises concerning the tableau method. So for example I need to show if a formula $X$ is tautology or not. So I have to check if ...
Apr 18, 2026
news
Vectors that form a triangle!
I have a problem here. How can I prove that sum of vectors that form a triangle is equal to 0 $(\vec {AB}+\vec {BC}+\vec {CA}=\vec 0)$ ?
Apr 18, 2026
news
Low rank approximation using CVX toolbox in Matlab
I try to use CVX toolbox to do "low rank approximation" work. The code is as follows: r = 2; % the rank; N = 32; % the dimension M = 32; a = randn(N,r); b...
Apr 18, 2026
