C1 and C2 DOUBTS HERE!!!!!

[The Golden Girl =D]

excuse me guys who have the c1 book plz
check up exercise
3E  question
4a and b

If you have the CD , Open it and there is a solution Bank "Capital letter S" press on it and you'll get to know the answer

But I already did that so Here is the Answer from the Cd's Solution Bank :


(a) a=1, b=-k, c=k+3
b2-4ac<0 for no real roots, so
k2-4(k+3)<0
k2-4k?12<0
(k-6)(k+2)<0
-2<k<6

(b) a=p, b=p, c=-2
b2-4ac<0 for no real roots, so
p2+8p<0
p(p+8)<0
-8<p<0


I hope I helped =D

[~ Miss Relina ~]

If you have the CD , Open it and there is a solution Bank "Capital letter S" press on it and you'll get to know the answer

But I already did that so Here is the Answer from the Cd's Solution Bank :


(a) a=1, b=-k, c=k+3
b2-4ac<0 for no real roots, so
k2-4(k+3)<0
k2-4k?12<0
(k-6)(k+2)<0
-2<k<6

(b) a=p, b=p, c=-2
b2-4ac<0 for no real roots, so
p2+8p<0
p(p+8)<0
-8<p<0


I hope I helped =D

oh no unfortunately i donot have the Cd
 but the thing which I donot undersatnd why did you use b2-4ac<0   
actually I used b2>4ac as the question asks for real roots that's my point and if u can plz explain thanks anyway

[The Golden Girl =D]

oh no unfortunately i donot have the Cd
 but the thing which I donot undersatnd why did you use b2-4ac<0   
actually I used b2>4ac as the question asks for real roots that's my point and if u can plz explain thanks anyway

I suggest you borrow it from someone , I found it very beneficial =] Or Perhaps check the Solution Bank that Ang3l posted

Delta is  b² - 4ac

There is NO such thing as B² > 4ac

if they say REAL roots it means greater than or Equal/Greater than.

if they say NO root then it is less than

then you solve it the way it was written in the solution bank =]

I hope you got my point =]

[~ Miss Relina ~]

I suggest you borrow it from someone , I found it very beneficial =] Or Perhaps check the Solution Bank that Ang3l posted

Delta is  b² - 4ac
There is NO such thing as B² > 4ac


if they say REAL roots it means greater than or Equal/Greater than.

if they say NO root then it is less than

then you solve it the way it was written in the solution bank =]

I hope you got my point =]

i know i ;m annoying by askin too much but i am sorry
why did you use delta b² - 4ac

and for that one ''' There is NO such thing as B² > 4ac'''
 i got it from  lesson no. 2.6 the note at the end of page 23
' all this is  in your mezan 7sanatik isa jazak Allaho Kairan ''

[The Golden Girl =D]

i know i ;m annoying by askin too much but i am sorry
why did you use delta b² - 4ac

and for that one ''' There is NO such thing as B² > 4ac'''
 i got it from  lesson no. 2.6 the note at the end of page 23
' all this is  in your mezan 7sanatik isa jazak Allaho Kairan ''

You're not annoying

There seems to be a misunderstanding here.

To be honest I never referred to the book if I misunderstood something since I ended up getting even more confused ,I always asked my private tutor or my teacher. So I'll take a Pic of the notes that talk about this and hopefully it'll clear your doubt =]

[~ Miss Relina ~]

You're not annoying

There seems to be a misunderstanding here.

To be honest I never referred to the book if I misunderstood something since I ended up getting even more confused ,I always asked my private tutor or my teacher. So I'll take a Pic of the notes that talk about this and hopefully it'll clear your doubt =]

oh now I am okay thanks alot dear

[The Golden Girl =D]

' all this is  in your mezan 7sanatik isa jazak Allaho Kairan ''

Ameen mate =] ... Wa Jazaki , Are you an Arab ?

oh now I am okay thanks alot dear

You're Welcome =]

[~ Miss Relina ~]

Ameen mate =] ... Wa Jazaki , Are you an Arab ?


You're Welcome =]

yes I'm an ARabian
 
but here is another problem
 in 3F Q 9
the method iI used to get the answer was b²- 4ac>0
and it works  anyways thhanks alot for previous notes posts they were really helpful
JAzakiAllah Kairan

[~ Miss Relina ~]

well in C1 sometimes they ask for finding the coordinates of points of intersection of cubic and quadratic equations so do I have to exactly the graph for each equation toget the points of intersection
or should I make the two equation equal to get the answer
Thanks in advance

[Malak]

well in C1 sometimes they ask for finding the coordinates of points of intersection of cubic and quadratic equations so do I have to exactly the graph for each equation toget the points of intersection
or should I make the two equation equal to get the answer
Thanks in advance

No, you dont have to sketch the graph exactly.
If you could actually post the Question then I can help better.

But check this website for great explanations: http://examsolutions.co.uk/A-Level-maths-tutorials/Edexcel/C1/index.php
It helped me a lot with C1.

[The Golden Girl =D]

yes I'm an ARabian
 
but here is another problem
 in 3F Q 9
the method iI used to get the answer was b²- 4ac>0
and it works  anyways thhanks alot for previous notes posts they were really helpful
JAzakiAllah Kairan

It is Arab not Arabian

I don't really get what You're saying.

You told me earlier that you wanted to solve exc 3E  Q 4a and 4b by  b² > 4ac

and I told you that that concept is wrong or in other words is not used to solve such Questions  as the Questions in  exc 3 E and 3 F .

so as I told you ,if you see the Words "Real Roots" you use greater than or Equal/ greater than

Here is the way it is solved in the Solution Bank

a=k, b=8, c=5
x={ - b plus or minus (square root ?b²?4ac) }/2a

b2-4ac greater than or equal  0 for real roots. So
82-4k * 5 greater than or equal 0
64-20k greater than or equal 0
64 less than or equal 20k
64 /20 less than or equal k
k less than or equal  3.2

I used less than or equal and greater than or equal since I wasn't able to find the  Symbols =,=

I hope you got it =]

You're Welcome ... Wa Jazaki

[The Golden Girl =D]

well in C1 sometimes they ask for finding the coordinates of points of intersection of cubic and quadratic equations so do I have to exactly the graph for each equation toget the points of intersection
or should I make the two equation equal to get the answer
Thanks in advance

Yes you just equate the Equations and get the Intersection Points between the TWO graphs in case there are TWO graphs to draw

But if it's just ONE graph then you have to solve as follow:

Firstly, you solve the equation as though that the X = 0  ,in other words you're finding the point of intersection of the graph with the y-axis.

Secondly, You solve the equation as though the Y = 0 , in other words you're finding the point of intersection of the graph with the x-axis.

I hope I cleared your doubt

No, you dont have to sketch the graph exactly.
If you could actually post the Question then I can help better.

But check this website for great explanations: http://examsolutions.co.uk/A-Level-maths-tutorials/Edexcel/C1/index.php
It helped me a lot with C1.

Seconded.

It helped me with  C1 , C2 as well as M1 ... You should check that website

[~ Miss Relina ~]

It is Arab not Arabian

I don't really get what You're saying.

You told me earlier that you wanted to solve exc 3E  Q 4a and 4b by  b² > 4ac

and I told you that that concept is wrong or in other words is not used to solve such Questions  as the Questions in  exc 3 E and 3 F .

so as I told you ,if you see the Words "Real Roots" you use greater than or Equal/ greater than

Here is the way it is solved in the Solution Bank

I used less than or equal and greater than or equal since I wasn't able to find the  Symbols =,=

I hope you got it =]

You're Welcome ... Wa Jazaki

well Thanks for the ARAB cuold you inbox me why
 and for the main mathematical issue
what I meant is that another example  which is  3F Q 9
I didnot use b² - 4ac < 0
but used b²-4ac > 0 can you clarify that

[~ Miss Relina ~]

No, you dont have to sketch the graph exactly.
If you could actually post the Question then I can help better.

But check this website for great explanations: http://examsolutions.co.uk/A-Level-maths-tutorials/Edexcel/C1/index.php
It helped me a lot with C1.

Thanks alot well if you want to get tired no problem for me 
well here we go :
aon the same axes sketch the curves given by y=(x-1)³ and y=(x-1)(1+x)
b find the coordinates of the points of intersection.

Thanks in advance

[The Golden Girl =D]

well Thanks for the ARAB cuold you inbox me why
 and for the main mathematical issue
what I meant is that another example  which is   3F Q 9
I didnot use b² - 4ac < 0
but used b²-4ac > 0 can you clarify that

Sure =]

In the Question it stated the words "Real root" , and when you see that then you should know that you should undoubtedly use " > or greater than or equal" .

How did I know that , look into these notes I posted prior


EDIT: Regarding your doubt about Sketching Graphs ,I found some notes that could help.

Attached.

Source of the Notes : http://getrevising.co.uk/resources/c1_sketching_curves