People can’t fucking wash a car

This is just a rant: my father owns a Ford, he thinks driving safely is for the white/developed nations and just because he does not live in one of them he does not need to drive like a sane man.

Anyway, to the topic, this man has time to do all other kinds of shit but not to wash his own car. He hires some guy to wash it. Good guy, has many years of experience. Then he sends in someone to cover for him while he does whatever.

The car had some discharge from a tree on it, so this guy goes “it doesn’t go away.” My father gave him a nylon scrubber to help the guy (yeah, utensils and car paint are the same). Now the entire thing is scratched.

It seems to be beyond everyone’s (those who are involved) comprehension that cars are not household items like utensils but expensive things which need systematic care rather than bullshit. Scrubbers at too rough for a shining painted surface, didn’t this occur to my family? Fuck this shit.

submitted by /u/Idiotnextdoor_2
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How can we find the maximal k dimensional cross section of a d dimensional hypercube?

Suppose we have a d-hypercube whose 2d vertices are those whose coordinates are either 1 or -1. Which k hyperplane can we construct such that its intersection with the cube will have maximal k-volume.

For example if we have d=2 and k =1 how can we construct a line such that it intersects the square (whose vertices are of the form (+-1, +-1) ) such that the intersection has maximal length? The line is a line that goes through two opposite vertices of the square.

How does this generalise to all regular polytopes is my main question. Any ideas/sources appreciated!!

submitted by /u/thenumbernumber
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How to check if time series is stationary? (with R programming language)

Hi guys, I must test stationarity of a time series. I use the function adf.test(timeSeriesData) {aTSA}, this function return a result the contains 3 components:

  • type1 (a matrix with three columns: lag, ADF, p.value, where ADF is the Augmented Dickey-Fuller test statistic)
  • type2 (same as above for the second type of linear model)
  • type3 (same as above for the second type of linear model)

If p.value < 0.05 the time series is stationarity. My problem is: which is the difference between type1, 2 and 3? In which case do I use the type X?

Thanks for your answers!

EDIT CODE:

result <- adf.test(signals[[nameOfSignal]]$data , output = FALSE) if(result$type1[,3]< 0.05){ print("Is stationary") 

submitted by /u/FuocoNegliOcchi
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curiosity on parallel lines and spheres

so…first: I’m not a math expert, second: I think this topic is moar like geometry but anyway…

if we have 2 parallel lines on a sphere they meet at the poles right? like the Longitudes of the earth. said this if we start “squashing” the sphere the lines keep on touching at the poles. if we keep doing this until we have something so similar to a plane that it is indistinguishable from it, the lines still meet at the pole… so is it right to say that parallel lines actually do meet…? and why doesn’t this happen for the latitude of the earth? because of technically speaking they to have the same proprieties of the longitudes.

submitted by /u/TheCubeMan4
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