The pdf associated to this problem is httpwwwcalpolyedujborz

The pdf associated to this problem is:

http://www.calpoly.edu/~jborzell/Courses/Year%2010-11/Fall%202010/Petersen-Linear_Algebra-Math_306.pdf

1 a)

Points in first quadrant of xy plane

Adding any two points in first quadrant gives another point in first quadrant

But, -1(1,1)=(-1,-1) which is not in first quadrant

Hence not closed under scalar multiplication but closed under addition

Consider the set of elements in first and third quadrant of xy plane

Take points: (1,2)+(-2,1)=(-1,3) which is not in first or third quadrant.

But it is closed under scalar multiplication