256
Science Discussion Forum / Re: Newton and his apple
« on: March 05, 2012, 03:18:42 PM »
Nice post
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257
Science Discussion Forum / What is an angle measure of regular 12 sided polygon?
« on: March 05, 2012, 03:18:05 PM »
Answer:
Each exterior angle measures 30 degrees
Each interior angle measures 150 degrees
Each exterior angle measures 30 degrees
Each interior angle measures 150 degrees
258
Science Discussion Forum / Cross product is not define in two space why?
« on: March 05, 2012, 03:15:15 PM »
why Cross product is not define in two space?
Answer:
When performing the cross product of two vectors (vector A and vector B), one of the properties of the resultant vector C is that it is perpendicular to both vectors A & B. In two dimensional space, this is not possible, because the resultant vector will be perpendicular to the plane that A & B reside in. Using the (i,j,k) unit vector notation, you could add a 0*k to each vector when doing the cross product, and the resultant vector will have zeros for the i & j components, and only have k components.
Answer:
When performing the cross product of two vectors (vector A and vector B), one of the properties of the resultant vector C is that it is perpendicular to both vectors A & B. In two dimensional space, this is not possible, because the resultant vector will be perpendicular to the plane that A & B reside in. Using the (i,j,k) unit vector notation, you could add a 0*k to each vector when doing the cross product, and the resultant vector will have zeros for the i & j components, and only have k components.
259
Science Discussion Forum / Re: importance of sleep...
« on: March 05, 2012, 03:07:00 PM »
yes it is indispensable
260
Science Discussion Forum / Re: Want to improve memory and learning: An hour of exercise daily can help
« on: March 05, 2012, 03:05:37 PM »
Nice post
261
Science Discussion Forum / Re: Tips for Public Speaking & Presentation Skills
« on: March 05, 2012, 03:04:37 PM »
good ideas
262
Science Discussion Forum / Re: perfect numbers
« on: March 05, 2012, 03:00:22 PM »
thanks for the complement
263
Science Discussion Forum / perfect numbers
« on: March 04, 2012, 04:08:36 PM »
In number theory, a perfect number is a positive integer that is equal to the sum of its proper positive divisors, that is, the sum of its positive divisors excluding the number itself (also known as its aliquot sum). Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself) i.e. σ1(n) = 2n.
The list of the perfect numbers are as follows:
6
28
496
8128
33550336
8589869056
137438691328
.......................
The four perfect numbers 6, 28, 496 and 8128 seem to have been known from ancient times and there is no record of these discoveries.
6 = 1 + 2 + 3,
28 = 1 + 2 + 4 + 7 + 14,
496 = 1 + 2 + 4 + 8 + 16 + 31 + 62 + 124 + 248
8128 = 1 + 2 + 4 + 8 + 16 + 32 + 64 + 127 + 254 + 508 + 1016 + 2032 + 4064
The list of the perfect numbers are as follows:
6
28
496
8128
33550336
8589869056
137438691328
.......................
The four perfect numbers 6, 28, 496 and 8128 seem to have been known from ancient times and there is no record of these discoveries.
6 = 1 + 2 + 3,
28 = 1 + 2 + 4 + 7 + 14,
496 = 1 + 2 + 4 + 8 + 16 + 31 + 62 + 124 + 248
8128 = 1 + 2 + 4 + 8 + 16 + 32 + 64 + 127 + 254 + 508 + 1016 + 2032 + 4064
264
Science Discussion Forum / Re: importance of sleep...
« on: March 04, 2012, 03:48:31 PM »
informative post
265
Faculty Forum / Re: Recent problem in our economy
« on: January 18, 2012, 11:46:52 AM »
We should go with the basis 'first earn then spend'.
266
Faculty Forum / Re: Alien : Get ready for new friend
« on: January 18, 2012, 11:44:03 AM »
thanks for this post
267
Faculty Forum / Re: Quotes from the Scholars
« on: January 18, 2012, 11:34:21 AM »
It is indispensable to maintain 'The quality of doing what is right and avoiding what is wrong'
268
Heritage/Culture / Re: Beautiful Place photos of Bangladesh
« on: January 17, 2012, 08:45:03 PM »
Exquisite
269
Heritage/Culture / Re: Our Origin and Identity
« on: January 17, 2012, 08:38:12 PM »
Thanks for the post.
270
Science Discussion Forum / Re: 10 Awesome Inventions of 2011
« on: January 17, 2012, 08:34:45 PM »
Thanks for the post.