[louci]

(Original post by megank)
can anyone help meeee?? please?
sin2x = -cos2x
how do i solve this? its so simple but i cant figure out how to do it
Thankyou x

urm
maybe if u square both sides
then use this rule sin^2x+cos^2=1
and apply it might work gonna try it myself

[Genesis2703]

(Original post by tinkerbell_xxx)
what is angle BC? :s

Why do you need BC for part ii)? (if you dont mean BAC) and anyway with the angle BAC you know from part i) you should be able to find the other angles with the sine rule, but I cant see why you need it.

(Original post by megank)
can anyone help meeee?? please?
sin2x = -cos2x
how do i solve this? its so simple but i cant figure out how to do it
Thankyou x

Divid both sides by cos2x, and then use a certain trig identity (involving Tan)

(Original post by katles)
Also... Another minor question but, when do you know when to leave a fraction as top heavy or mixed? Sometimes in the mark scheme it's mixed and sometimes not. Would I still get a mark if I left it in a different form?

It doesn't matter, the mark scheme always says e.g. 5 1/3 and in the comment column "or any identical answer". So it does not matter

[katles]

(Original post by Genesis2703)
It doesn't matter, the mark scheme always says e.g. 5 1/3 and in the comment column "or any identical answer". So it does not matter

Thank youuu

[master y]

anyone know where i can do lots of practise log questions.... how to be good at them overnight??

[louci]

Divid both sides by cos2x, and then use a certain trig identity (involving Tan)



ohh yeahhh!!!
man took me time to figure that out !!!

good one genesis

[megank]

Ohhhh i see thankyouuu

[a10]

Lets smashhh this exam tomorowwwww woooooo! Done all the past papers from 07 till January 2012 hopefully its easy

[tinkerbell_xxx]

(Original post by master y)
anyone know where i can do lots of practise log questions.... how to be good at them overnight??

it took me about a week of revision classes, try mymaths then the exam papers

[peachesandcream77]

I've come across a question on Jan 11 ocr c2, that says find the sum of 200 where n = 101. it's one of those sequence symbols.. what does this mean?!

i dont understand the n = 101 part.

[a10]

Everyone feeling confident about tomorow? What grades is everyone wanting % wise?

[tinkerbell_xxx]

[QUOTE=Genesis2703;37598379]Why do you need BC for part ii)? (if you dont mean BAC) and anyway with the angle BAC you know from part i) you should be able to find the other angles with the sine rule, but I cant see why you need it.

i did that now, but the mark scheme for part 3 confuses me, ive found angle C but the mark scheme says to do 290 - angle C

or 210 + angle A

but i dont get why

[megank]

can anyone kindly help me with a question...
its 9ii) i dont understand the question and which values of x to use...
Thank you..!

Is it just from 0-2? so 0, 0.5, 1, 1.5, 2?

[erniiee]

(Original post by Genesis2703)
Im going to use A for arithmetic and G for geometric

A1=G1 therefore a = a
A2=G2 therefore a+d = ar
A3=G4 therefore a+2d = ar^3

A1 + A3 = 2A2 therefore G1 + G4 = G2, therfore a + ar^3 = 2(ar)

See where it is going?

And yeah I meant for that, I dont know how to solve a cubic in this case without factor theorum, but it just didnt feel very mathematical taking a factor out that way without being told to like normal.

EDIT: Yes the log thing was a deduction, but I am not very intelligent so yeah I do not notice these things

Yea I see. Thanks for this btw and then what would you have done?

And oh, I don't mean a deduction from my part ha, its just in my book it doesn't really state it as a rule, it just says that this implies this and so use it to effect - tbh I think it is basically a rule, as its the whole point of logs, right?

[Genesis2703]

(Original post by peachesandcream77)
I've come across a question on Jan 11 ocr c2, that says find the sum of 200 where n = 101. it's one of those sequence symbols.. what does this mean?!

i dont understand the n = 101 part.

I'm suprised they would ask this in C2, as this is something that we did in FP1, I do recall seeing it a couple times though but I think it is a little mean.

The symbol is called Sigma (capital sigma), and the number on top of the sigma is the final value N, the value on the bottom is the 1st value used. So in this case the question is asking for the sum of the values from 101 to 200 (not 1 to 200 like normal).

To do this you do the sum to 200 using the regular formula, and then the sum of 100 with the formula, and do Sum200 - Sum100, to leave to numbers from 101-200 left.

[QUOTE=tinkerbell_xxx;37598621]

(Original post by Genesis2703)
Why do you need BC for part ii)? (if you dont mean BAC) and anyway with the angle BAC you know from part i) you should be able to find the other angles with the sine rule, but I cant see why you need it.

i did that now, but the mark scheme for part 3 confuses me, ive found angle C but the mark scheme says to do 290 - angle C

or 210 + angle A

but i dont get why

Because you are looking for the angle that goes from the north of C to the parth CA CLOCKWISE. You know the the angles from the left of north C to BC is 70, (as the angle above it at B is 110, like in part i), then you are left with angle BCA, which you find, then do 360 - BCA - 70 = answer, so 290 - BCA.

(Original post by megank)
can anyone kindly help me with a question...
its 9ii) i dont understand the question and which values of x to use...
Thank you..!

Is it just from 0-2? so 0, 0.5, 1, 1.5, 2?

Yes it is, the curve you are after has an asymptote with the x-axis, i.e. it never touches it, meaning subbing y=0 into it wont find any x-intercept, you were meant to take the hint that the upper limit was 2, and there were 4 strips of 0.5 and work backwards to 0 (it also says area bound by the axis).

(Original post by erniiee)
Yea I see. Thanks for this btw and then what would you have done?

And oh, I don't mean a deduction from my part ha, its just in my book it doesn't really state it as a rule, it just says that this implies this and so use it to effect - tbh I think it is basically a rule, as its the whole point of logs, right?

Well, what I did then was rearrange and take the common factor of a out, which leaves you witht he equation they asked for.

Yeah lets call it s log rule, saves the arguments

[megank]

[QUOTE=Genesis2703;37598804]I'm suprised they would ask this in C2, as this is something that we did in FP1, I do recall seeing it a couple times though but I think it is a little mean.

The symbol is called Sigma (capital sigma), and the number on top of the sigma is the final value N, the value on the bottom is the 1st value used. So in this case the question is asking for the sum of the values from 101 to 200 (not 1 to 200 like normal).

To do this you do the sum to 200 using the regular formula, and then the sum of 100 with the formula, and do Sum200 - Sum100, to leave to numbers from 101-200 left.

(Original post by tinkerbell_xxx)

Because you are looking for the angle that goes from the north of C to the parth CA CLOCKWISE. You know the the angles from the left of north C to BC is 70, (as the angle above it at B is 110, like in part i), then you are left with angle BCA, which you find, then do 360 - BCA - 70 = answer, so 290 - BCA.



Yes it is, the curve you are after has an asymptote with the x-axis, i.e. it never touches it, meaning subbing y=0 into it wont find any x-intercept, you were meant to take the hint that the upper limit was 2, and there were 4 strips of 0.5 and work backwards to 0 (it also says area bound by the axis).



Well, what I did then was rearrange and take the common factor of a out, which leaves you witht he equation they asked for.

Yeah lets call it s log rule, saves the arguments

Oh okay... i didnt quite understand their wording but after your explanation i get it now Thank you very much..! im sure you'll ace it tmr

[Genesis2703]

(Original post by megank)
Oh okay... i didnt quite understand their wording but after your explanation i get it now Thank you very much..! im sure you'll ace it tmr

I'm aiming for 90+ getting 89 was annoying in C1 as I am aiming for A* in Maths and Further maths, and it would have knocked my confidence if it wasnt for my FP1 score, I learned my lesson not to neglect these early Core units even though they are viewed as easier by many people, because towards your AS and A2 they are worth the same amount of UMS.

I hope I will do well, I seem to be helping out a lot so I cant be that bad :P

I did the May 2011 paper just before and got 72/72 so Im feeling good, I almost slipped up at the end, with a 2x graph I nearly took an x value and halved it again, but I realised while checking though the question

[erniiee]

(Original post by master y)
anyone know where i can do lots of practise log questions.... how to be good at them overnight??

Hm try the attached sheets. Answers are there too.

[peachesandcream77]

am i right in thinking that geometric progressions converge when r is between 1 and -1. i've come across june 10 ocr question 9b where it says, given the geometric progression converges, find the exact value of r

the previous question gives you a polynomial, r^3 - 2r + 1. i have to factorise this, so would i do (r-1) than find the other roots from there?

[megank]

(Original post by Genesis2703)
I'm aiming for 90+ getting 89 was annoying in C1 as I am aiming for A* in Maths and Further maths, and it would have knocked my confidence if it wasnt for my FP1 score, I learned my lesson not to neglect these early Core units even though they are viewed as easier by many people, because towards your AS and A2 they are worth the same amount of UMS.

I hope I will do well, I seem to be helping out a lot so I cant be that bad :P

I did the May 2011 paper just before and got 72/72 so Im feeling good, I almost slipped up at the end, with a 2x graph I nearly took an x value and halved it again, but I realised while checking though the question

Wow!! Good Luck im sure you'll be able to do it easily.. do you want to study maths at uni? :O

I need a high ish UMS in C2 too because i cant do mechanics so my C2 needs to be high to balance it out... cuz i think the D1 paper next week will be horrible

[erniiee]

(Original post by Genesis2703)
Well, what I did then was rearrange and take the common factor of a out, which leaves you witht he equation they asked for.

Yeah lets call it s log rule, saves the arguments

Oh okay, I'm worried I wont know what to do in the exam or even if I do get the answer, the way I've used is ridiculous ha.

I agree