MedVision ad

Q15 (1 Viewer)

Rafy

Retired
Joined
Sep 30, 2004
Messages
10,719
Gender
Female
HSC
2005
Uni Grad
2008
Discuss your answers to Q15 here.
 

lolcakes52

Member
Joined
Oct 31, 2011
Messages
286
Gender
Undisclosed
HSC
2012
Re: General Thoughts: Mathematics Ext 2

I put my solutions to 16 here http://community.boredofstudies.org/showthread.php?t=293623
for 15
ai) simple expansion of the difference of two roots being greater than zero
aii) (x-1)>=0 , y-x>=0 multiply and your done
aiii) the left inequality is part ii, the right is part i.
iv) didn't attempt

bi) conjugate root theorem, mention that the conjugate of ia is -i*the conjugate of a.
ii) split the third term of the polynomial into two parts and factorise the two parts
iii) didn't do
iv) product of the roots, then say something about how conjugate alpha times alpha is the modulus of alpha
v) sum of roots
vi)didnt do
 

v1

Active Member
Joined
Jun 9, 2012
Messages
219
Gender
Undisclosed
HSC
2012
Q15
a) (iv) using iii) 1<=j<=n
sqrt(n) <= sqrt(j(n-j+1)) <= (n+1)/2
let j=1,2,3...n and multiply them all
sqrt(n^n) <= sqrt([1*2*3....*n][n*(n-1)*(n-2)...1] <= [(n+1)/2]^n
sqrt(n^n) <= sqrt([n!][n!]) <= [(n+1)/2]^n
sqrt(n^n) <= n! <= [(n+1)/2]^n
 
Last edited:

SoresuMakashi

Member
Joined
Aug 28, 2012
Messages
37
Gender
Male
HSC
2012
Q15
a) (iv) using iii) 1<=j<=n
sqrt(n) <= sqrt(j(n-j+1)) <= (n+1)/2
let j=1,2,3...n and multiply them all
sqrt(n^n) <= sqrt([1*2*3....*n][n*(n-1)*(n-2)...1] <= [(n+1)/2]^n
sqrt(n^n) <= sqrt([n!][n!]) <= [(n+1)/2]^n
sqrt(n^n) <= n! <= [(n+1)/2]^n
Very nice.
 

KappaD

New Member
Joined
Oct 19, 2011
Messages
13
Gender
Male
HSC
2013
Sorry, but how did you guys do b) iii)? Having a durp moment here
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top