C1 MEI Wednesday 16th May 2012

Reply 80

xfearless

7

Original post by Axion

Aspiring

P: y^3 >1
Q: y>1

which way does arrow go if any?

q<=>p

Reply 81

alex7892

2

Ahhh fair, and thanks you too!

Reply 82

jordan95

OP

Original post by AspiringGenius

So can anybody ask me some questions please, some harder ones to get my mind in the set for mathsy? :biggrin:

i) The centre of a circle lies on the midpoint of A(3,5) and B(7,9)
Given that the point (1,4) lies on the circumference of this circle, find the radius, and hence, the equation of the circle.

ii) Using the radius obtained in part i), state the equation of another circle of which the point (1,4) lies on the circumference.

Look, I even made the questions MEI-ish! I hope they're reasonably difficult, or at least at Section B standard!

Reply 83

Neuro Alex

11

I am retaking this tomorrow after scoring 78 last exam, not revised massively but am confident as I only scored (relatively low) because I panicked as oppose to any gaping holes in knowledge.

Hope to be able to answer everything and score high :-) good luck all!

Reply 84

Rtcw

14

Quite interesting is that so many in here re-take it even though they're already achieved B, I wonder why. I had D in back then and I am retaking it in hopes of B to A.

Reply 85

tehforum

20

Original post by Rtcw

Quite interesting is that so many in here re-take it even though they're already achieved B, I wonder why. I had D in back then and I am retaking it in hopes of B to A.

Get easy UMS - every little helps, especially when it comes to getting the full A-level.

Reply 86

Axion

15

Original post by xfearless

q<=>p

correct

Reply 87

Axion

15

Lol RTCW has turned up here after his disgraceful post which you can read below:

http://www.thestudentroom.co.uk/showthread.php?t=2001630&p=37563478

Reply 88

jordan95

OP

Original post by Axion

Lol RTCW has turned up here after his disgraceful post which you can read below:

http://www.thestudentroom.co.uk/showthread.php?t=2001630&p=37563478

'lethaless'- that's an interesting word, can't say I've come across it before.

Reply 89

LosMutos

i hate thoes <=> things. can someone please explain it to me?

Reply 90

Rtcw

14

Original post by Axion

Lol RTCW has turned up here after his disgraceful post which you can read below:

http://www.thestudentroom.co.uk/showthread.php?t=2001630&p=37563478

How is this related to this thread?

Reply 91

jordan95

OP

Original post by LosMutos

i hate thoes <=> things. can someone please explain it to me?

P=>Q This means P implies Q, so the details of P imply that the details of Q are correct. For example, if P is 'a square' and Q is 'a quadrilateral with 4 equal sides', then P implies Q as a square must meet the requirements of Q in order to be a square. However, Q doesn't imply P because a rhombus is also a quadrilateral with four equal sides.

P<=Q This means P is implied by Q, so the details of Q imply that the details of P are correct. This is essentially the reverse of the above.

P<=>Q This means P implies and is implied by Q, so the details of Q and P imply each other, and are interdependent. For example, if P is 'a square' and Q is 'a quadrilateral with four equal sides and four right angles', P and Q imply each other.

Hope that helps a little...

Reply 92

LosMutos

Original post by jordan95

P=>Q This means P implies Q, so the details of P imply that the details of Q are correct. For example, if P is 'a square' and Q is 'a quadrilateral with 4 equal sides', then P implies Q as a square must meet the requirements of Q in order to be a square. However, Q doesn't imply P because a rhombus is also a quadrilateral with four equal sides.

P<=Q This means P is implied by Q, so the details of Q imply that the details of P are correct. This is essentially the reverse of the above.

P<=>Q This means P implies and is implied by Q, so the details of Q and P imply each other, and are interdependent. For example, if P is 'a square' and Q is 'a quadrilateral with four equal sides and four right angles', P and Q imply each other.

Hope that helps a little...

Oh I see. Thank you very much :smile:

Reply 93

xfearless

7

Could someone explain how to go about questions like this?
Find the real roots of the equation x^4-5x^2-36=0 by considering it as a quadratic equation in x^2
I'm not sure what they're really asking me to do.

Reply 94

-strawberry-

14

Original post by xfearless

Could someone explain how to go about questions like this?
Find the real roots of the equation x^4-5x^2-36=0 by considering it as a quadratic equation in x^2
I'm not sure what they're really asking me to do.

When you put a, b and c into the quadratic equation, see what number the discriminant (the bit under the square root) is. If it's greater than 0, it has 2 roots, if it is 0 then it has 1 root and if it's less than 0 it has none. You can just carry on with the equation to then find the roots :smile:

Reply 95

Alotties

10

x^4-5x^2-36=0

you pretend it is a x^2 equation and use the quadratic formula
so: a = 1, b = -5 and c = -36
and you go from there to see if it has real roots or not

(or that is what i would do, anyone feel free to correct me)

Original post by xfearless

Could someone explain how to go about questions like this?
Find the real roots of the equation x^4-5x^2-36=0 by considering it as a quadratic equation in x^2
I'm not sure what they're really asking me to do.

Reply 96

jordan95

OP

Original post by xfearless

Could someone explain how to go about questions like this?
Find the real roots of the equation x^4-5x^2-36=0 by considering it as a quadratic equation in x^2
I'm not sure what they're really asking me to do.

You have to treat it like a quadratic, where you could have (x+a)(x-b). However, as it is a quartic equation your factorisation must be of the form (x^2+a)(x^2-b) because x^2 multiplied by x^2 gives x^4 but bear in mind I'm using +a and -b purely to illustrate the generic form.

Reply 97

xfearless

7

ah great, thank you both!

Reply 98

blackroses19

anyone got any tips on how to do the best i can

Reply 99

alex7892

2

Hi again guys. Real quick question when diving a square root by 2 such as in the -b+- b2-4ac
------------
2a

If the number in the square root was 68 then divided it by 2, is it the same as dividing the number in the sqaure root by 4?

What abouts if the a=2 so you were dividing the sqaure root by4 ? would it be the same as dividing the number in the sqaure root by 16? :L Hope you guys know where i'm coming from, its just for simplifying an answer.

Also, is anyone going to post an unnoficial mark scheme after the exam tommorow? :P

C1 MEI Wednesday 16th May 2012

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