• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

09'ers so you think you can do maths? (2 Viewers)

Kurwa

Member
Joined
Apr 3, 2009
Messages
53
Location
In your room ............
Gender
Male
HSC
2008
I see you guys/girls seem to complain way too much over maths, so i have decided to make a thread similar to "4unit revising game" but this one will consist of questions that will test you knowledge on "maths"...

So here it comes :jedi:

question 1) Consider the quadratic equation

x^2-(2cos@)x+1 =0

which has roots alpha and beta...

find an expression for alpha and beta and hence prove that alpha^10 + beta^10 = 2cos(10@)

it will be a good practice for your trails + hsc xD
 

Timothy.Siu

Prophet 9
Joined
Aug 6, 2008
Messages
3,449
Location
Sydney
Gender
Male
HSC
2009
AB=1
A+B=2cos @
A=1/B
B2-2cos@ B+1=0
B=[2cos@ +- root(4cos2@-4)]/2
=cos@+-root(i^2(1-cos^2 @))
=cos@+-i|sin @|

therefore
B=cos@+isin@
A=cos@-isin@
A^10+B^10=(cos@+isin@)^10+(cos@-isin@)^10
=cos10@+isin10@+cos10@-isin10@
=2cos 10@
 

Kurwa

Member
Joined
Apr 3, 2009
Messages
53
Location
In your room ............
Gender
Male
HSC
2008
mc yeh i did do 4unit..

relax ladies the first one is usually the easy one =]

plus im not gaining notthin from this im doing uni maths xD
 

Kurwa

Member
Joined
Apr 3, 2009
Messages
53
Location
In your room ............
Gender
Male
HSC
2008
round 2-

Prove that (1+itan@)^n + (1-itan@)^n = 2sec^n@cosn@

Hence prove that

Re(1+itan(pi/8))^8 = 64(17-12root2)

as you can see i dont target specific chapters!
 

Kurwa

Member
Joined
Apr 3, 2009
Messages
53
Location
In your room ............
Gender
Male
HSC
2008
AB=1
A+B=2cos @
A=1/B
B2-2cos@ B+1=0
B=[2cos@ +- root(4cos2@-4)]/2
=cos@+-root(i^2(1-cos^2 @))
=cos@+-i|sin @|

therefore
B=cos@+isin@
A=cos@-isin@
A^10+B^10=(cos@+isin@)^10+(cos@-isin@)^10
=cos10@+isin10@+cos10@-isin10@
=2cos 10@
make life easier by using quadratic formula xD

its alot better than using alpah + beta = ...
 

vds700

Member
Joined
Nov 9, 2007
Messages
861
Location
Sydney
Gender
Male
HSC
2008
round 2-

Prove that (1+itan@)^n + (1-itan@)^n = 2sec^n@cosn@

Hence prove that

Re(1+itan(pi/8))^8 = 64(17-12root2)

as you can see i dont target specific chapters!
have i stumbled across the general maths forum??
 

samthebear

Member
Joined
Sep 7, 2008
Messages
319
Location
Sydney
Gender
Female
HSC
2009
maybe it's because no one really gives a toss about this thread and only really want to post on here to ridicule you. Spend your time doing something more productive =] you deffinately deserve to do something worth your while.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 2)

Top