Some questions about Subject in GR9768

[cauchy2012]

Hi,guys, I am doing the practice tests and have several problems in it. They are: GR9768#19, I cannot figure out the second table;GR9768#48, this one is really tough, I just can eliminate B,C and E,but cannot select from A and D; GR9768#57, hope someone can explain for me this; GR9768#59, really confused;

Thank you all guys!!!

[Napot]

#19

3rd column has two a's.

#57

Just check the ring axioms. 2 isn't closed under addition. You can get a polynomial whose degree is odd

[cauchy2012]

#19

3rd column has two a's.

#57

Just check the ring axioms. 2 isn't closed under addition. You can get a polynomial whose degree is odd

Thank you, I can figure out as you said, what about #48&#59? I still cannot work it out

[blitzer6266]

For 59: http://www.mathematicsgre.com/viewtopic ... 3156#p3156

for 48, rewrite v as v= u - x^(1/3) + 1

As x ranges from 0 to 1, this gives a family of lines with slope 1

Because v=1+y ranges from 1 to 2 as y ranges from 0 to 1, the image looks like A

[cauchy2012]

For 59: http://www.mathematicsgre.com/viewtopic ... 3156#p3156

for 48, rewrite v as v= u - x^(1/3) + 1

As x ranges from 0 to 1, this gives a family of lines with slope 1

Because v=1+y ranges from 1 to 2 as y ranges from 0 to 1, the image looks like A

Thank you so much!