**HL Maths P2 Before/After

mathstalk

Rebels101 wrote: »

I used co-ordinate geometry said since the circle is tangent to x and y the centre must be (x,y) but also x equals y! then i did perpendicular distance formula from centre to line and got k=1 or k=2+root2 so took the second one!

Ah, I just turned everything into nice, simple triangles. Then I sine ruled the shít out of it until I got an answer. Bam! Hopefully it's accepted.

tanzy

mathstalk wrote: »

No, I got something like this:

Ye, I'm pretty sure that's right. I just remembered i drew the arc of length PQ instead of PQ-QR.

montown

Mista wrote: »

Squares and rectangles are parallelograms?

/facepalm

Mista

Rebels101 wrote: »

I used co-ordinate geometry said since the circle is tangent to x and y the centre must be (x,y) but also x equals y! then i did perpendicular distance formula from centre to line and got k=1 or k=2+root2 so took the second one!

I think i worked out g and f as 1+root2 (or something), and then did a translation of (1,1) (which i knew as the point of intersection of the other tangent). It was a really weird translation, but i got an answer similar to that

DepoProvera

Got no answers earlier... what did yous get for 2nd and 3rd part of probability question?

tanzy

RedTexan wrote: »

Kind of, I think that's a little more correct than my answer, what did ye say for the first part, a degree error in alpha or beta and for what reason?

For the first part i said alpha and that beta will affect the error more if it is smaller than 48 degrees. I said this because the radius of arc length that alpha affects would be greater in size than radius of arc length that beta affects.
Sorry if that made barely any sense, it's quite hard to explain.

ImFudged

Was it just me or was maths super easy. Finished half an hour early

tacofries

I got k=2.9

I done this by using the perpendicular distance to a line(the line being the tangent and the point being the center of the circle) and equated it to the radius. I got two answers due to the + or - and they were k=1, and k=2.9

I forget how i got the radius so maybe i made a wrong assumption there :P

I also got a=36 and B=100 degrees in question 8(mother****** b*tch of a question haha).

I got 94% increase for the battery one.

P.s. Does that graph in post 363 look like a ....... good owl SEC havin the craic hahaha

Hermione Granger

Osric wrote: »

I did simultaneous equations in g, and got k=5.828

I used the fact that the midpoint (1,1) of the line segment on x+y=2, from the y-intercept (0,2) to the x-intercept (2,0), is on the circle. Then the equation of the diameter/radius is x=y (can be proven using perpendicular slope), so g=f. Since the graph is touching both axes, g^2=c. From that I solved for g, and took the bigger answer (g=radius, so smaller answer would give a tiny circle). Then used perpendicular distance formula from (1,1) to the other line, and got k=5.828, or k is negative

Same !!!! Got it in the last second

What did people get for the angle beta ??

Messed up my q 8 at the end but other than that it could have been a lot worse :P

ECM2012

I got 94% increase too. But I got 44 for alpha and 100 for bet

RedTexan

Hermione Granger wrote: »

Same !!!! Got it in the last second

Sweet, surely can't be a coincidence that 3 of us came out with such a strange figure!

Hermione Granger

RedTexan wrote: »

Sweet, surely can't be a coincidence that 3 of us came out with such a strange figure!

Hopefully what did you get for the g value ?

Got something like a 1.17 percent increase ...

tacofries

RedTexan wrote: »

Sweet, surely can't be a coincidence that 3 of us came out with such a strange figure!

5.8 is twice 2.9, i wonder did i miss something

Pepperr

I guess I should post some of the answers I can remember...

For the circle question I got k = 7 (I got the centre as 4,4 and translated from 1,1 to 4,4 and then to the second tgt which gave me 7,7. sub into the line, 7 + 7 = 2k, k = 7!

My battery question percentage was in around the 90%'s

And..For my alpha and beta angles I got like 26 and 100, but I only did the cosine rule twice, I forgot to add the second half of the Alpha angle >.< RAGING! Forgot about the tails in the illustrate Q too..There goes the A probably.

RedTexan

Hermione Granger wrote: »

Same !!!! Got it in the last second

What did people get for the angle beta ??

Messed up my q 8 at the end but other than that it could have been a lot worse :P

Yeah and I did a different method to your's (which sounds correct by the way), one which I am not going to run into to! But when you got the radius you could have just said said it must be greater than 2 and that left me with one solution! Ye reckon what they were looking for in part (ii) and (iii) of 8 was a spiel on how the arc is greater due to a longer radius and so on?

RedTexan

Hermione Granger wrote: »

Hopefully what did you get for the g value ?

Got something like a 1.17 percent increase ...

2+root2 for the centre co-ordinates, pretty much my whole class had that?

ImFudged

tacofries wrote: »

I also got a=36 and B=100 degrees in estion 8(mother****** b*tch of a question haha)

I got 81 and 121 degreea I think

Togepi

Last part of that was unusually techy. Glad I do DCG for once!

Anyway, am I the only one who got 45 for alpha and 90 for beta? Everyone keeps saying they got 100 for beta and I heard a few different results for alpha, none of them 45. :cool:

Hermione Granger

RedTexan wrote: »

2+root2 for the centre co-ordinates, pretty much my whole class had that?

Yep same !! Am I dont know about 8 to honest
i had something similar to the picture above but i had da part in the middle shaded .. Hopefully they'll mark it easy :P

I got beta equal to 100 alpha = 44

Osric

Togepi wrote: »

Last part of that was unusually techy. Glad I do DCG for once!

Anyway, am I the only one who got 45 for alpha and 90 for beta? Everyone keeps saying they got 100 for beta and I heard a few different results for alpha, none of them 45. :cool:

I got 45 for alpha, and 100 for beta

DepoProvera

The answer is beta 100 alpha 44 that's what I and most seem to have... Yous have slowly eroded my confidence in the paper :L

acorn1702

I got 28 for alpha and 80 for beta? haha

Bubbleope

i'll be lucky if i pass
only thing i could do was the last question and i never even saw a question like that in me life!? i answered most of the questions in english too!? WHAT WERE ALL THE WEIRD ASSEDWORDS like causality and arrears and all this shítebollocks. /: not impressed with it at all. i hate project maths.
although i did do better in it than how i did in paper one.
i can only be hopeful now. /: (: /: aaah

reznov

Definitely 100 for beta.
36 - 50 for alpha I believe.

Chavways

I think I got 83 for beta and 28 for alpha.I found the distance between p and r to be 25 I think and used cosine rule.

DepoProvera

I'm fairly certain it's 44 I doubled checked in the exam :L

screeeewed

reznov wrote: »

Definitely 100 for beta.
36 - 50 for alpha I believe.

I got 80 for beta first...but it was obtuse so I just took it from 180 and got 100..do ya think that will be accepted.?:o and I got like 46 or something for alpha...:o what did Ye do for the graph though in question 8..:O I thought that question was a balls:(

mcpaddington

RedTexan wrote: »

Hermione Granger wrote: »

Same !!!! Got it in the last second

What did people get for the angle beta ??

Messed up my q 8 at the end but other than that it could have been a lot worse :P

Yeah and I did a different method to your's (which sounds correct by the way), one which I am not going to run into to! But when you got the radius you could have just said said it must be greater than 2 and that left me with one solution! Ye reckon what they were looking for in part (ii) and (iii) of 8 was a spiel on how the arc is greater due to a longer radius and so on?

The value for alpha and beta can change you guys, therefore as long as the distance between p and r is 25 any values for alpha and beta are correct. As long as their correct abviously.

Adolescenteen

Chavways wrote: »

I think I got 83 for beta and 28 for alpha.I found the distance between p and r to be 25 I think and used cosine rule.

Same here. Overall don't know what to make of the paper. It was difficult, but not as bad as it first looked. Made a balls of Q5 alright and the final part of the robotic arm, but I answered everything. Fearing though that my good work in P1 will be brought down by P2.

gethepoints

Igot screwed in paper 2... I was NOT expecting that paper. I did all the sample papers in Folens exam papers and they were nothing like it.

I calculated my marks.. 160 in paper 1 and 105 in paper 2. That's a pass. Fek it all i want is the extra 25 points!