Author Topic: Additional Math Help HERE ONLY...!  (Read 75156 times)

Offline ramezamgad

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Re: Additional Math Help HERE ONLY...!
« Reply #30 on: May 30, 2009, 08:21:02 pm »
lil^$tar

what is the relative velocity of two particles A and B moving

a) towards each other A with velocity 10 and B with velocity 15????
b) in the same direction A with velocity 10 and B with velocity 15????
c) in the same direction A with velocity 15 and B with velocity 15????

vanibharutham
what is the domain of the first eq.?

Offline vanibharutham

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Re: Additional Math Help HERE ONLY...!
« Reply #31 on: May 30, 2009, 08:32:53 pm »
x greater than or equal to 0...

sorry the symbol dint come up on there
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Offline ramezamgad

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Re: Additional Math Help HERE ONLY...!
« Reply #32 on: May 30, 2009, 08:37:20 pm »
well
y=ln(4x-1)
u have to find what value of x makes y=0
ln1=0
so 4x-1=1
4x=2
x=1/2

u made 4x-1=0 which is a common mistake

Offline vanibharutham

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Re: Additional Math Help HERE ONLY...!
« Reply #33 on: May 30, 2009, 08:43:18 pm »
oh... silly me!

right, and then for the domain x > 1/2

you'll have to find the range, which is y > 0

THANKS SO MUCH...
i always make that mistake with domain and range when it comes to e^x and ln(x)
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Offline ramezamgad

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Re: Additional Math Help HERE ONLY...!
« Reply #34 on: May 30, 2009, 08:48:53 pm »
an easy method to remember is that the domain of f(x) is the range of f-1
and the range of f(x) is the domain of f-1

Offline vanibharutham

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Re: Additional Math Help HERE ONLY...!
« Reply #35 on: May 30, 2009, 08:53:49 pm »
You are a genius! :D

thanks for that :P

remind me thank you over nd over agen :P
A genius is 1% intelligence, 99% effort.

Offline lil^$tar

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Re: Additional Math Help HERE ONLY...!
« Reply #36 on: May 30, 2009, 09:08:53 pm »
lil^$tar

what is the relative velocity of two particles A and B moving

a) towards each other A with velocity 10 and B with velocity 15????
b) in the same direction A with velocity 10 and B with velocity 15????
c) in the same direction A with velocity 15 and B with velocity 15????

vanibharutham
what is the domain of the first eq.?
a)25 b)-5 c)0
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Offline ramezamgad

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Re: Additional Math Help HERE ONLY...!
« Reply #37 on: May 30, 2009, 09:14:16 pm »
b is not -ve
u just need to know that B will move faster than A and the distance between them will decrease until they become side to side then the distance between them will increase
hope u find that easy

Offline lil^$tar

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Re: Additional Math Help HERE ONLY...!
« Reply #38 on: May 30, 2009, 09:26:12 pm »
thanks very much +rep 4 u
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Offline Ghost Of Highbury

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Re: Additional Math Help HERE ONLY...!
« Reply #39 on: May 31, 2009, 08:33:09 am »
Hi,

i was doing the following question:

The function f(x) = [ (ex + 1) / 4 ] for the domain x ? 0


i) Obtain an expression for f-1
ii) State the domain and range for f-1

The first part was easy...
i got the answer, and when i checked it with the mark scheme i got the right answer, which was:
ln(4x-1)

The second part of my answer didn't match the mark scheme, and i dont seem to understand the why.

The domain, according to me should be:

x > 1/4

The range should be:

f-1(x) > -3.2188

However, the mark scheme says that the answers are:

DOMAIN: x > 1/2
RANGE: f-1(x) > 0

could some one please explain my mistake?

which paper did this question appear in..
year/month/paper..
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Offline Ghost Of Highbury

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Re: Additional Math Help HERE ONLY...!
« Reply #40 on: May 31, 2009, 10:15:21 am »
plzz answer,...which paper???
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Offline vanibharutham

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Re: Additional Math Help HERE ONLY...!
« Reply #41 on: May 31, 2009, 03:17:16 pm »
Adi M...

May/ June 2003 Paper 2  Cambridge
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Offline shan2391

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Re: Additional Math Help HERE ONLY...!
« Reply #42 on: May 31, 2009, 04:45:15 pm »
Guys i dont know how to find the amplitude and period of function plzz help.
Ref: Q.8 OCt/NOv08 Paper2

Offline vanibharutham

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Re: Additional Math Help HERE ONLY...!
« Reply #43 on: May 31, 2009, 07:46:55 pm »
Shan2391

The question states that

f(x) = 3 + 5 sin2x

Im sure you can easily rearrange that to make it simpler:

f(x) = 5sin2x + 3

The amplitude is always going to be the number infront the trignometric function...
In this case the amplitude will 5 :)

simple,

if forexample f(x) was 25000sin2x, your amplitude would be 25000


Your amplitude involves the actual trignometric identity... in this case... 2x.

Always remember this rule:
To find the period of any trignometric graph, divide the coefficient of x by 360 (but in this case 2pi as we are dealing with radians)

Therefore our period is 180 degrees or simply pi.

Hope that helped
A genius is 1% intelligence, 99% effort.

Offline shan2391

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Re: Additional Math Help HERE ONLY...!
« Reply #44 on: May 31, 2009, 08:55:48 pm »
Shan2391

The question states that

f(x) = 3 + 5 sin2x

Im sure you can easily rearrange that to make it simpler:

f(x) = 5sin2x + 3

The amplitude is always going to be the number infront the trignometric function...
In this case the amplitude will 5 :)

simple,

if forexample f(x) was 25000sin2x, your amplitude would be 25000


Your amplitude involves the actual trignometric identity... in this case... 2x.

Always remember this rule:
To find the period of any trignometric graph, divide the coefficient of x by 360 (but in this case 2pi as we are dealing with radians)

Therefore our period is 180 degrees or simply pi.

Hope that helped
Thanks a lot man
but what does +3 show in a graph