Vectors question

[cheehai]

http://i58.photobucket.com/albums/g268/cheehai/problem5.jpg

here's the problem, i'm oblivious to as to what conditions ii, iii, iv, mean, i have never seen that notation and its not *in my notes nor my book.

Can someone help me out? Also for problem b) can someone point me in the right direction.

Cheers

*edit

so far for b) i has
b) a•w = 4a - 1b - 3c , b•w = 1a + ab + 2c ==> w•(a+b) = w•a + w•b = a - c

a = c + 1
by substituting the above into b•w i got
b = 3 + c

...

are thar any sites that will teach this to me? i dunno what i'm doing.

[cheehai]

can anyone tell me what conditions ii, iii, and iv mean, WTF doesnt anyone know, i've asked me mates and they are just as clueless as i am. is you guys not helping me because i havent started solving the question? i cant solve it if i dont understand what it asks me... please some help. 40 views and not a single post :( i feel unloved.

[cheehai]

http://i58.photobucket.com/albums/g268/cheehai/corrected.jpg

alright, here's the corrected question :D and how i plan to arrive at the answer. unless conditions ii. iii. iv. slice in to the cones; then i'll have to do some more pondering. but otherwise i think i have the first question solved.

can anyone give me a hint of two for question b) this assignment is dues tomorrow...

the approach i'm taking is to differentiate |w| to find the minimum but before i can do that i have to express it as a single variable. Is this right? or am i taking the back door?