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# Vectors Q2 watch

1. Vyjby
2. (Original post by Deeboss)

So far I think that for a+b, you do x2-x1, and y1+y2? Also I am not so sure on how to get a-b? or the 5a? Someone please help!
If a = (x1, y1) and b = (x2, y2) then

a + b = (x1 + x2, y1 + y2).

a * b = x1y1 + y1y2

5a = (5x1, 5y1)

Can you apply this to your question?
3. (Original post by Zacken)
If a = (x1, y1) and b = (x2, y2) then

a + b = (x1 + x2, y1 + y2).

a * b = x1y1 + y1y2

5a = (5x1, 5y1)

Can you apply this to your question?
So the answer would be a + b = (*1, 3); a * b = (3, 1); 5a = (5, 2).?
4. Sorry i dont know why it replaces the -'s with *'s can you ignore all of the asterisks they are meant to be -'s. Can you explain it one more time please?
5. (Original post by Deeboss)
Sorry i dont know why it replaces the -'s with *'s can you ignore all of the asterisks they are meant to be -'s. Can you explain it one more time please?
So a + b= (1, 2) + (-2, 1) = (1+ -2, 2 + 1) = (-1, 3) like you said.

a - b = (1, 2) - (-2, 1) = (1--2, 2-1) = (3, 1) like you said.

5a = (5*1, 5*2) = (5, 10) - note that you multiply the second number as well.
6. (Original post by Zacken)
So a + b= (1, 2) + (-2, 1) = (1+ -2, 2 + 1) = (-1, 3) like you said.

a - b = (1, 2) - (-2, 1) = (1--2, 2-1) = (3, 1) like you said.

5a = (5*1, 5*2) = (5, 10) - note that you multiply the second number as well.
Ohh okay thanks alot understand alot better now to take notes.

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