Thread: Linear Algebra space

i did the work just i need more details and justify by stating axions and theorems,, please help

2) Let V be the set of all pairs (x,y) of real numbers with the addition + and scalar multiplication* defined by:
(x1,y1)+(x2,y2)= (x1 + x2 , y1+y2) and c*(x,y)=(x,cy)

Show that V with the above operation is not a vector space. Find at least one axiom that fails and give an example showing that the axiom fails!!!..
***Let α = (x, y)
Then for real numbers a and b we have
(a + b) α = (a + b) (x, y)
= ( x, (a+b)y )

Now aα = a(x, y)
= (x, ay)
bα = b(x, y)
= (x, by)
and aα + bα = (x, ay) + (x, by)
= ( 2x , ay + by)
[IMG]file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/msohtml1/01/clip_image001.gif[/IMG] (a + b) α
Therefore, V is not a vector space.

thanks

Originally Posted by cris123

i did the work just i need more details and justify by stating axions and theorems,, please help

2) Let V be the set of all pairs (x,y) of real numbers with the addition + and scalar multiplication* defined by:
(x1,y1)+(x2,y2)= (x1 + x2 , y1+y2) and c*(x,y)=(x,cy)

Show that V with the above operation is not a vector space. Find at least one axiom that fails and give an example showing that the axiom fails!!!..
***Let α = (x, y)
Then for real numbers a and b we have
(a + b) α = (a + b) (x, y)
= ( x, (a+b)y )

Now aα = a(x, y)
= (x, ay)
bα = b(x, y)
= (x, by)
and aα + bα = (x, ay) + (x, by)
= ( 2x , ay + by)
[IMG]file:///C:/DOCUME%7E1/ADMINI%7E1/LOCALS%7E1/Temp/msohtml1/01/clip_image001.gif[/IMG] (a + b) α
Therefore, V is not a vector space.

thanks

what is your problem then? as i see it, there is nothing wrong with your proof..