Brahmagupta's Identity
Man, i really need to write abt this nifty maths thingy man
(a^2 + b^2)(c^2 + d^2) = (ac-bd)^2 + (ad+bc)^2
Its know as the Brahmagupta's Identity. For a long time, i knew it as heng2 den3 shi4, because my chinese was so bad i couldn't read the first few words ... then i found out that that just means identity ... was so sad, started calling it the 'product of 2 numbers, each of which can be written as the sum of 2 squares, can be written as the sum of 2 squares' theorem, and thats a mouthful.
Heres another way to remember it, as pointed out by Dr Tay TS. MATRIX MULTIPLICATION!
*a b **c d ***ac-bd **ad+bc
-b a X -d c = -bc-ad **ac-bd
[Darn it, can do spacing...]
NICE!
(a^2 + b^2)(c^2 + d^2) = (ac-bd)^2 + (ad+bc)^2
Its know as the Brahmagupta's Identity. For a long time, i knew it as heng2 den3 shi4, because my chinese was so bad i couldn't read the first few words ... then i found out that that just means identity ... was so sad, started calling it the 'product of 2 numbers, each of which can be written as the sum of 2 squares, can be written as the sum of 2 squares' theorem, and thats a mouthful.
Heres another way to remember it, as pointed out by Dr Tay TS. MATRIX MULTIPLICATION!
*a b **c d ***ac-bd **ad+bc
-b a X -d c = -bc-ad **ac-bd
[Darn it, can do spacing...]
NICE!
posted by calvinlinzw at
1:23 AM
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Broadband Guy, at 1:30 AM
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