Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win


Math / Science

The Math / Science topic primarily includes discussions of mathematics, physics, statistics and economic analysis, but also biology, chemistry and other sciences.

Share tech news, updates, or what's on your mind.

Sign up to Post

Hi Experts,

I have tried to round off a value x = 455.77 using math .round() function but not rounded the value 466.

Code I have given to round off:

var rounded = Math.Round(x, 2, MidpointRounding.AwayFromZero);

Open in new window

Could you guys please explain whats wrong here?

Anjala Baby
Enroll in October's Free Course of the Month
LVL 10
Enroll in October's Free Course of the Month

Do you work with and analyze data? Enroll in October's Course of the Month for 7+ hours of SQL training, allowing you to quickly and efficiently store or retrieve data. It's free for Premium Members, Team Accounts, and Qualified Experts!

Dear Experts,

Actually learning the basic of Machine Learning through the following link:


That contains an url url = "https://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data" which have the data of 150 records from the iris dataset, but I would like to test the results on more records.

Could you please advise is there on the internet availabe more iris data for free to download?

Thanks in advance,
Hey, All,

Can you give me some good web links to where it has some very good Data Scientist Resume samples? Also, those samples are one-pagers (everyone desire one page resumes)

Watching this 6 minute video, I leaned HAARP shoots 72,000 times the maximum amount of energy for an AM station in the United States.


My question is what's a better analogy?

For example, how much energy is that compared to the output of a small nuclear plant?

I am just having a hard time sensing the scope of the comparison they created and hope someone can come up with a better description.

I believe electrical cable length can be measured by sending a signal down it and timing the reflections from the unterminated end..  

see https://electronics.stackexchange.com/questions/39745/rs485-cable-lengths-and-reflections

Is there a similar method to measure the length of metal pipes or bars of say 15 mm and up cross section.. I guess in theory it should work. But ruling again this is the lack of insulation, very large cross section. Perhaps a metal bar will not work like a wave guide.  

i am searching for method to sense the lenght of lengths of track.. Just by touching a probe electrically.

I've recently been trying to learn more about color codes and complementary colors, particularly when using the color boxes in Microsoft Office apps. I'd appreciate answers to questions and comments regarding accuracy/inaccuracy of the following notes:

• RGB is an initialism representing Red, Green, & Blue
• RGB code uses a scale of 0-255 in order to maintain a 1:1 ratio with hexadecimal values (since 16^2 = 256).
• RGB numerical values have nothing to do with complementary colors.

• HSL is an initialism representing Hue, Saturation, & Luminosity where
• Hue is the color as measured between 0° and 360° on the color wheel (with 0° representing red).
• Saturation is the dullness vs brightness measured between 0% & 100% (with 0% = gray with no color and 100% = full saturation).
• Luminosity is the darkness vs lightness (with 0% = black and 100% = white).

• Different colors are complementary when saturation is kept constant.

Is there a linear relationship between the 0-255 scales used in the MS Office color box for Hue, Saturation, & Luminosity and the scales described above? In other words:
• is one tick on the H scale equivalent to 1.4118° (360°/255 = 1.4118)?
• is one tick on the S & L scales equivalent to 0.3922% (100/255 = 0.3922)?

What method/formula is used to convert between the two systems?

I do not have the information at my fingertips to do these calculations, and am doubtful if I have the math do support such a comparison.

Here's my new favorite site regarding Bitcoin usage and transactions, which may provide some key stats.


I am wondering what the odds are for the fastest ASIC processor of winning the prize of submitting the next blockchain update compared to the odds of some popular Lottery, so I picked Mass Powerball. From what I have learned, each GPU that is "playing the game" is merely submitting a series of picks, like Powerball.

The first GPU to submit the winning numbers, wins.

Once we have the prospects for the fastest ASIC, we can then look for the average hardware that is "playing the game" to find how low those odds become. That would be a follow-on question.

Anyone want to try and make that comparison?
I saw on History Channel that HAARP shoots up 72,000 times the energy as the most powerful AM radio station in the lower 48.


Where does this energy come from?

I would like to know how to compute the x-intercepts of a cubic graph based in a given equation. If there is a formula that does this, then i would like to know this formula, if not then i would like to know the steps required to compute said values.

I have a statistics questions pertaining to evaluating a process.   Please see attached Excel which uses an analogy to illuminate the underlying problem.  

Upon opening the Excel, please refer to the two yellow boxes which includes the scenario.   Also, the green text box includes a quote from a colleague who reviewed the matrix.   He suggested that the proposed math (in cells C13:J13) is incorrect.  

My question and the underlying problem is shown in the blue text box.   I would welcome any thoughts on this relatively simple statistical approach.   Please provide reasoning (and maybe a link to website) so that I can learn more about this particular situation.
What does it mean to be "Always On"?
What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Hi,  I am looking to design a profit sharing scheme that would take into account the job level of the employee, the performance of the geographic region, and the individual performance level.  The first can be a number between 1 and 7 or a dollar amount, the second will be the achievement of projected profit, and the third will be a number between 1 and 5.  Is there anyway to calculate a final contribution without making it the percentage of a cap?  The total pool for each geographic regional will be a straight percentage of profits.

i.e. 15% of profits might be 10 million for ease of calculation.  For thirty employees, is there some formula that will reward each employee a portion of that 10 million based on their job level, achievement of projected profit, and ind. performance???

Thank you!
what property describes the number sentence?

6 + 0 = 6
A dice is rolled until the game is stopped. The game stops when there is a 4,5, or 6. For every number 1,2, or 3 the score increases by +1. If the game stops with a 4 or 5, the accumulated score is paid. If the game is stopped with a 6 then there is no payoff. What is the expected payoff of the game.

I thought about it as follows:
The probability that the game stops with 4 or 5 is 2/3. The probability that payoff is 0 is 1/2 that is I get 4 or 5 in my first throw. The probability that payoff is 1 is (1/3)*(1/2) i.e. I either get 1,2 or 3 in my first throw and 4 or 5 in the second.
The probability that payoff is 2 is (1/3)^2*(1/2) i.e. I either get 1,2 or 3 in my first and second throws and 4 or 5 in the third.
Then the expected value is :
2/3*sum of((1/3)^n*(1/2))*n ,where n ranges from 0 to infinity.

However, this is not giving me the correct solution which is 2/3. Also, how can I solve it using recursion?

M.S. Steel ingot size is defined by having one bottom square base of side 3.5" and top square base of side 4.5".Both base are connected by length equal to 58". Basically it's a tapered ingot.
A relative told me bitcoin mining doesn't require us to pay anything, virtually 0 risk
& we get decent returns from it.  

1. Anyone can point me to articles (for newbie) on how to get started

2. Is it truly low-risk or no-risk?
If some butterflies can travel at 60km/hour how far will they travel in 1 minute
I am wondering if anyone has any feeling for the error rate on any of:

- Iris scans
- Face recognition
- Finger print

I was just wondering...

What should I expect by forking the BitCoin open source code? What kinds of things can one do in customizing the code?

What language(s) is it in? What platform does it run on?

What about the code run by Bookkeepers? And the generation of the BlockChain database updates?

And lastly, what "engine" determines which algorithms need to be mined and what is managing the connections to this peer-to-peer network?

Free Tool: Port Scanner
LVL 10
Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

I am new to reading up on BitCoin but was fascinated to be reminded that in the early days of BitCoin, people "mined" additional BitCoin on their PC's. As far as I recall, this was in exchange to turning over part of the processing power of their PC's to BitCoin for background processing.

I assume this amounted to a massive amount of additional processing power available to BitCoin.

Does anyone recall the primary uses of that kind of processing horsepower?

Why do they not need this today?

Can computers today perform at such a higher rates, this "mining" is no longer needed?

Could the addition of a BlockChain database have removed the need for this kind of processing?

Stupid question, please see attached.  When measuring the actual shortest distance between SFO to Amsterdam is shows 5,425mi.  The airplane route shows longer 10k+ miles.   Why wouldn't the flight goes the shortest distance?  Or is it how the distance vs measurement shows on the map just for user's simplicity?  

google maps
Let's say I have 10 different categories. Each category can have a variable number of numeric values. Some might have 12 values. Some might have 8, Some might have 16.

I want to get the average of the values in each category to determine which category has the highest average (and so on down to the lowest).

However, it doesn't seem "fair" that one category is only averaging 8 values, but another is averaging 16.

So, I'd like to even this out, if possible, so that all category averages act like there are only averaging 10 values.

Does that make sense?

How would I go about doing this? Would I, for example, on the category with 16 values, do something like VALUE*(10/16) for all 16 values and then use the result of that formula to calculate the average? For example, if one of the property's value is 4, I'd do 4*(10/16) = 2.5?

That doesn't seem like it would be the ideal way to do it, however. I toyed around with PERCENTILE, but I don't think that would do the trick, either.

Any ideas?
Hi everyone. How do I model this in Excel? It isn't a homework question, but a real life example of why they made you do these types of problem in math class.

I am borrowing $30000 to buy a car. There is an option available to get 0% financing, but only for 24 months, which would make a monthly payment of $1250. I also have access to a line of credit which has an rate of 3.5%. Currently I have $500 per month I can pay from my account. What would total cost of borrowing be if I took the 0% loan, paid $500 a month from my account and the remaining $750 from the line of credit. Then after 24 months, I would then use the $500/mo from my account to pay back the line of credit.

I have attached a spreadsheet showing the cost of just financing the whole thing on LoC vs the cost of the above in two stages. Just wanted to be sure that it is correct.
My friend is maths teacher in high-school abroad, she also has a masters in maths from there as well.

When she comes to US, she want to continue to teach the same subject here in US school. Can you please let me know what are some prereqs/steps for this kind of situation? like would it make sense to do a masters in math from US as well, to get into teaching in high-school, easily or would be more than that? etc

thank you
Dear experts:
Can someone please help me clarify the criteria to determine n and r in Permutations and combination. I think I am solving these problems by thumb rule rather on a proper understanding.
Below I have listed a few questions along with solutions where r is greater than n or i am not sure how allocate n ways to r blanks. Please help.

We know that the number of ways of filling up r blanks with n dissimilar things is nPr. The first blank can be filled with any one of the given n things in n ways.
Below I have a few examples:
Q1 In how many ways can 7 women go to 9 restaurants?
      1      2      3      4      5      6      7      8      9      
R blanks                                                            
N ways                                                            
The Permutation given is 97
Clarification: How do I determine which is n and which is r?

Q2 In an examination paper there are 8 questions each with 4 answer choices and 5 questions each with 2 answer choices. The no. of ways of answering the question if all the 13 questions are attempted is?
The Permutation given is 48 * 25
Clarification: How do I determine which is n and which is r?
Q3 In how many ways can 5 letters be posted in 6 boxes?
The Permutation given is 65
Clarification: How do I determine which is n and which is r?

Please help. Thank you

Math / Science

The Math / Science topic primarily includes discussions of mathematics, physics, statistics and economic analysis, but also biology, chemistry and other sciences.