DSE 2006 paper discussion

[phelps.phan]

Qn 16:Pls clarify if two adjacent columns/rows are interchanged the sign changes right? Isn't the answer b?
Qn 37: how to do?

[Gayyam]

For 16, the question states that the matrix is singular. Thus, det(A) = 0.

Had it been non-zero, the sign would've changed. But here, it stays the same.

For 37, f(x) = (x^2 + 2*x - 1)/x = x + 2 - 1/x.

Now, as x tends to 0, you can see that -1/x will heavily outweigh x+2, therefore f(x) tends -1/x at values of x close to 0. Therefore the y axis is an asymptote.
As x tends to infinity, x+2 heavily outweighs -1/x. Therefore, f(x) tends x+2 for large x. Thus, y=x+2 is also an asymptote.

[phelps.phan]

thank u Gayyam

[phelps.phan]

pls someone explain 50, 51. Thanks.

[yuganshi]

Please help me with q 31  32 and 33...

[yuganshi]

@ phelps  
For q50 what would definately not occur is option d because trade will definately occur due to differrnces in opportunity costs in production of goods of the two country ... hence both countries would not produce both goods

[The Villain]

@yuganshi
31. Cases
case 1 :X wins first
XX,XZYXX,XZYXZXX,....and so on
Case 2: X does not win first
YZXX,YZXYZXX, and so on

It will be a G.P.
I hope you got it...

[yuganshi]

@villain
yeah got it ... thanks :)

[rongmon]

Q31/ 32/ 33.

I don't quite follow.

Could you share the workings?

[rongmon]

Got 'em.

Thanks.