Author Topic: math in hl HELP  (Read 9154 times)

Offline slvri

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Re: math in hl HELP
« Reply #30 on: December 03, 2009, 04:37:27 pm »
zeroes of g? never heard of the zeroes of a function b4 :-\
i hate A level...........

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #31 on: December 03, 2009, 05:35:54 pm »
Same as the roots

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #32 on: December 03, 2009, 05:49:09 pm »
When i get home

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #33 on: December 03, 2009, 10:01:19 pm »

let g(x) = log5|2log3x|=0
2 log3x=1 so x=sqrt(3)
Have I got the question right? I can only see one root.

Offline IGSTUDENT

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Re: math in hl HELP
« Reply #34 on: January 23, 2010, 06:19:25 am »
Posting my queries:

1.prove that cos^6(x)+ sin^6(x)=1/8(3cos4x+5)

2.Prove that tan5x=(5tanx-10tan^3(x)+tan^5)/(1-10tan^2(x)+5tan^4(x)). By considering the equation tan5x=0, show that tan^2(pi/5)=5-2sqrt5.

For the 2nd question I was able to do the first part but not the second

Thanks

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #35 on: January 23, 2010, 11:09:14 am »
if tan5x=0 x=tan^-10= pi/5
0=(5tanp-10tan^3 p +tan^5 p)=tanp(5 -10tan^2 p+tan^4 p)
hence solve t^2-10t+5=0 where t=tan^2 p and p=pi/5

Offline cooldude

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Re: math in hl HELP
« Reply #36 on: January 23, 2010, 11:35:46 am »

Offline IGSTUDENT

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Re: math in hl HELP
« Reply #37 on: January 24, 2010, 12:49:06 am »
if tan5x=0 x=tan^-10= pi/5
0=(5tanp-10tan^3 p +tan^5 p)=tanp(5 -10tan^2 p+tan^4 p)
hence solve t^2-10t+5=0 where t=tan^2 p and p=pi/5

thanks a lot

Offline sweet777

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Re: math in hl HELP
« Reply #38 on: January 30, 2010, 09:27:33 am »
can u please help me solve this matrix question??

Write 5A2-6A=3I in the form AB=I and hence find A-1 in terms of A and I

please help fasssssssssttttttttttttt!!!!!!!!!!!!!!!!!!!!!!!

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Re: math in hl HELP
« Reply #39 on: January 30, 2010, 09:58:49 am »
wats GP


Geometric Progression, I guess.

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #40 on: January 30, 2010, 01:45:57 pm »
Few mins

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #41 on: January 30, 2010, 01:52:10 pm »

Write 5A2-6A=3I in the form AB=I and hence find A-1 in terms of A and I
5A^2-6A+1=4I so (A-I)(5A-!)=4I so A-1= 4I(5A-1)^-1

Offline IGSTUDENT

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Re: math in hl HELP
« Reply #42 on: April 21, 2010, 11:38:58 am »
Need help in a few questions:

1)The polynomial p(x) + (ax+b)3 leaves a remainder of -1 when divided by x+1 and a remainder of 27 when divided by x-2.Find the values of the real numbers a and b.

2)Given that the roots of the equation x3-9x2 +bx -216 =0 are consecutive terms in a geometric sequence find the value of b and solve the equation.

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #43 on: April 21, 2010, 12:27:44 pm »
1)x+1=0 so x=-1 p(-1)=(-a+b)^3 =-1 so -a+b=-1 (1)
x-2=0 so x=2 p(2)=(2a+b)=3 so 2a+b=3 (2)
(2)-(1) 3a=4 so a=4/3
b=a+1 =7/3

I did the other one already somewhere - I will try to find a link

Offline astarmathsandphysics

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Re: math in hl HELP
« Reply #44 on: April 21, 2010, 12:28:45 pm »
The orrts are anyway 1,6,36