Question 21174: Hi..I have one more problem..and I don't even know where to start..
I'm given..
A=[0, -1, 0, 4, 0, 2, 8, 1, 7]; B=[2, 1, -3, 4, 1, 6]
(a) Find 3A-2B
(b) Find AB
Please help!
Cecilia
Answer by venugopalramana(3286)   (Show Source):
You can put this solution on YOUR website! A=[0, -1, 0, 4, 0, 2, 8, 1, 7]; B=[2, 1, -3, 4, 1, 6]
(a) Find 3A-2B
(b) Find AB
3A MEANS MULTIPLY EACH ELEMENT IN A WITH 3...ALSO IN SETS REPETETIVE ELEMENTS DO NOT MATTER AND THEY CAN BE DROPPED.FURTHER,THE SEQUENCE OF PLACING THE ELEMENTS CAN BE CHANGED AS DESIRED.SO
A=[0,-1,4,2,8,7]..ALSO IT IS A GOOD PRACTICE TO PUT THE ELEMENTS IN SOME ORDER ..SAY INCREASING ORDER..SO WE GET
A=[-1,0,2,4,7,8]..NOW 3A =[3*-1,3*0,3*2,3*4,3*7,3*8]=[-3,0,6,12,21,24]
SIMILARLY 2B=[-6,2,4,8,12]
NOW X-Y MEANS SET OF ALL THOSE ELEMENTS IN A WHICH ARE NOT PRESENT IN Y ..SO
3A-2B=[-3,0,6,12,21,24]-[-6,2,4,8,12]=[-3,0,6,21,24]..SINCE -3 IS IN 3A BUT NOT IN 2B...ETC..WHERE AS 12 IS IN 3A AND 2B ..HENCE IT IS NOT IN THE ANSWER.NOTE THAT THIS - IS DIFFERENT FROM FROM WE DO IN ARITHMATIC.
***************************************
BY AB YOU MEAN AXB I THINK OR CARTESIAN PRODUCT OF 2 SETS.IT IS SET OF ALL POSSIBLE ORDERED PAIRS WITH ELEMENTS OF A AS THE FIRST ELEMENT AND ELEMENTS OF B AS THE SECOND ELEMENT...SO WE GET
AXB=[-1,0,2,4,7,8]X[-3,1,2,4,6]=[(-1,-3),(-1,1),(-1,2),(-1,4),(-1,6),(0,-3),(0,1),(0,2),(0,4),(0,6),(2,-3)........ETC...YOU CAN COMPLETE I SUPPOSE ....
|
|
|
