Qualification > Math
Additional Math Help HERE ONLY...!
vanibharutham:
I heard cambridege added the A* for this course
it will be somewhere around 85%
and they will move the A grade lower to around 80%??
do u think thats a fair claim?
Padapop:
--- Quote from: vanibharutham on June 01, 2009, 09:39:15 am ---I heard cambridege added the A* for this course
it will be somewhere around 85%
and they will move the A grade lower to around 80%??
do u think thats a fair claim?
--- End quote ---
Where did u hear that from? Can someone provide links/evidence etc?
It would be awesome if a* = 85% and not a= 85% cause i think thats a bit hard.
archangel:
can someone help with the straight line exponential graphs?
the kind where they ask u to express y in terms of x... then u have to make it y=mx+c
vanibharutham:
Archangel
Straight line exponential graphs ...
Right :P
here we go...
Normally the question will give you a table of values containing two variables from which a scientists carried a certain experiment. When they plotted their values they don't get a straight line.
You will either be told two things:
1) a formula by which the variables are supposed to be connected by
2) to plot something against something
So first, they will give you the table of values:
x: 2 3 4 5 6
y: 9.2 8.8 9.4 10.4 11.6
If they tell you to plot something against something, it is much easier. For the above table of value draw the graph of xy against x2
From the above information you know you need to find the values of x2 and the values of xy.
Ok,
so lets find the values of x2 first:
well simple
4, 9 , 16, 25, and 36
The values of xy
18.4, 26.4, 37.6, 52 and 69.6
Thus giving us the follow coordinates to plot:
(4,18.4) , ( 9,26.4), (16, 37.6), (25, 52) and (36, 69.6)
All you have to now do is plot those points do convert your exponential graph into a straight line graph...
Then you can easily find the gradient of the graph by using
y2-y1
x2-x1
basically the gradient will be:
26.4 - 18.4 = > 8/5 or 1.6
9 - 4
To find the c - value just read off your graph
In this case, your c value should approximately be 12.2
However let me show you the algebric way of solving to find c...
Use any co ordinate, with your y - iontercept co ordinate
Which means ( 25, 52 ) and ( 0 , c )
Find the gradient of those two points
you will end up with
c - 52
0-25
But that equals to 1.6 (beecause we have already found the value for m)
therefore, c - 52 = - 40
c = 12
Now you can simply replace your Y = mX + C formula
which is
xy = 1.6x2+12
just rearrange to get y in terms of x
(question taken from may/june 2003 paper 1 cambridge )
archangel:
--- Quote from: vanibharutham on June 01, 2009, 11:21:04 am ---Archangel
Straight line exponential graphs ...
Right :P
here we go...
Normally the question will give you a table of values containing two variables from which a scientists carried a certain experiment. When they plotted their values they don't get a straight line.
You will either be told two things:
1) a formula by which the variables are supposed to be connected by
2) to plot something against something
So first, they will give you the table of values:
x: 2 3 4 5 6
y: 9.2 8.8 9.4 10.4 11.6
If they tell you to plot something against something, it is much easier. For the above table of value draw the graph of xy against x2
From the above information you know you need to find the values of x2 and the values of xy.
Ok,
so lets find the values of x2 first:
well simple
4, 9 , 16, 25, and 36
The values of xy
18.4, 26.4, 37.6, 52 and 69.6
Thus giving us the follow coordinates to plot:
(4,18.4) , ( 9,26.4), (16, 37.6), (25, 52) and (36, 69.6)
All you have to now do is plot those points do convert your exponential graph into a straight line graph...
Then you can easily find the gradient of the graph by using
y2-y1
x2-x1
basically the gradient will be:
26.4 - 18.4 = > 8/5 or 1.6
9 - 4
To find the c - value just read off your graph
In this case, your c value should approximately be 12.2
However let me show you the algebric way of solving to find c...
Use any co ordinate, with your y - iontercept co ordinate
Which means ( 25, 52 ) and ( 0 , c )
Find the gradient of those two points
you will end up with
c - 52
0-25
But that equals to 1.6 (beecause we have already found the value for m)
therefore, c - 52 = - 40
c = 12
Now you can simply replace your Y = mX + C formula
which is
xy = 1.6x2+12
just rearrange to get y in terms of x
(question taken from may/june 2003 paper 1 cambridge )
--- End quote ---
AHH THANK YOU SO MUCH! +rep
so basically, its just substituting and altering the eqn in the form y=mx+c
man, exams are 2 days away, and i havent opened my book yet :P
im going for intensive tution for 4 hours tmrw... get that brain working. :)
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