[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 323

 
Integer писал(а) >>


You can do the math in a Windows calculator.


Yes, it works. 10947302325566084787191541568-10924622727902378924946084413-22679597663705862245457125=30
It's even funny.
 
(-283059965.0)*(-283059965.0)*(-283059965.0)+(-2218888517.0)*(-2218888517.0)*(-2218888517.0)+(2220422932.0)*(2220422932.0)*(2220422932.0)=0.0 (!=30)
30 does not work.
Genetics finds for number 29=(-3)^3+(-2)^3+(4)^3 and 29=(1)^3+(1)^3+(3)^3. For 30 it is not possible to find
 
joo >>:
(-283059965.0)*(-283059965.0)*(-283059965.0)+(-2218888517.0)*(-2218888517.0)*(-2218888517.0)+(2220422932.0)*(2220422932.0)*(2220422932.0)=0.0 (!=30)

joo, how did you calculate this - in your mind?

by genetics finds for number 29=(-3)^3+(-2)^3+(4)^3 and 29=(1)^3+(1)^3+(3)^3. Can't find any for 30

Well, I wrote that the solution above is the first one found. Before that, no representation of 30 as a sum of three cubes of integers was known.

 
Mathemat >>:

joo, это ты как считал - в уме, что ли?

Дык я ж написал, что решение выше - первое найденное. До этого никаких представлений 30 в виде суммы трех кубов целых известно не было.

Not in my mind of course. Just checked - the sum of the three cubes is 0, not 30.

 
What did you test it with?
Richie also checked it - on Integer's advice:
10947302325566084787191541568-10924622727902378924946084413-22679597663705862245457125=30<br / translate="no">
 
Mathemat >>:
А на чем проверил?
Richie тоже проверил - по совету Integer'a:

not 30, but 10947302325566084787191541568-1092462272790902378924946084413-22679597663705862245457125=-180388626432

MQL counts wonderfully

 
joo писал(а) >>

не 30, а 10947302325566084787191541568-10924622727902378924946084413-22679597663705862245457125=-180388626432

>> MQL wonders


VB counts too, but it gives out rubbish. Try it on a Windows calculator.

 
joo, here's what I dug up in the Help (MQL4 Reference - Language Basics - Data Types - Integer Constants (int)):
Integer constants can take values from -2147483648 to 2147483647. If the constant exceeds the specified range, the result is undefined.
 

By the way, the last 6 digits of the numbers: 541568-084413-457125=30

 
Mathemat >>:
joo, вот накопал в Помощи (Справочник MQL4 - Основы языка - Типы данных - Целые константы (int)):

Calculated in double numbers.

But there will still be zeros after the 16th digit, that's why the result is the same.

I'll try to work around this limitation without using string variables.

Reason: