 # rinik

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## Community Reputation

19 Good ## Profile Information

• Gender
Male
• Exams
May 2014
• Country
Macedonia
1. Pearson or IBID I have all the textbooks you mentioned and the Cambridge and H&H textbooks. I feel that the Pearson one is the best. It has questions exactly like the ones on the exams. It has info and help on the investigation. In my opinion it follows the syllabus better than the rest of the textbooks.
2. I am done with math HL but it would be fun to practice with you guys I sent a request.
3. ## What calculator is best suitable for Maths HL

I used the TI-84. It's all you will need for the exams. I would buy nspire cx for something like a portfolio or a project. However you can find computer software that will be a lot more helpful than a gdc for that sort of stuff. So my advice would be to not waste the money if you don't have it. During your exam you will use your calculator to sketch a graph, find zeros, find max min, solve problems with probability distribution and solve some integrals. The TI-84 is more than capable at doing that and it's a lot easier to use than some older models.
4. ## Math HL paper 3 sets, relations and groups

Thank god I am not the only one
5. I am expecting somewhere around 90 marks. I did not find it easy. However my definition of easy is scoring above 105 marks. I also felt that it was longer than previous papers.
6. a) In T minutes there will be T/4 cars and hence the parameter you use is 0.25T P(X<=3)= P(0)+P(1)+P(2)+P(3)=0.6 Substitute 0.25T as the parameter in the equation and solve using a gdc. for example P(0)= (0.25T)^0*e^(-0.25T)/0! do this for all of the probabilities and you get an equation with one unknown, T b) A ferry can carry a max of 3 cars. That means that a total of 6 can arrive because if more arrive than it will take another 10 minutes to transport all of the cars. This means that at least 3 have to arrive in the first 10 minutes because if 4 or more cars arrive in the second 10 minutes you will need another 10 to transport all of the cars. The new parameter is 10/4=2.5 There are 4 possibilities No more than 3 cars arrive in the first 10 minutes and no more than 3 cars arrive in the next 10 minutes 4 cars arrive in the first 10 min and no more than 2 arrive in the next 10 5 cars arrive in the first 10 minutes and no more arrive than 1 in the next 10 6 arrive in the first 10 minutes and no more than 0 arrive in the next 10 minutes. no more than= cumulative distribution Just multiply the values for each situation and add up all 4 situations and you get the required probability. Use poissonpdf and poissoncdf or this will take you forever. Edit: you can also do this with a lot longer method. Using the same parameter and the fact that there can be a max of 6 cars you can calculate the probabilities individually for everything and sum them up P(0)P(0)+P(1)P(0)+P(2)P(0)+P(3)P(0)+P(3)P(1)..............................P(6)P(0). Try expanding the cumulative probabilities in the previous method and you will see that both expressions are the same I am writing this to show you that the probabilities when less than 6 cars arrive are present in the first method
8. You don't know what you want. I am not trying to be mean! Sit down and think about what you want to achieve or present with your essay. Medicine is a large field and all the topics you mentioned above are also very broad. Try to define a few research questions and after that try to think of a way to approach those questions. Ask people here or do some research. 4000 words might seem a lot but you will hit the limit very fast if you don't focus on one single thing. I did a math EE however it's still has not been graded. During the first month I was basically doing the same thing as you. Searching for a topic but with no goal. I wasted a lot of time like this. When I finally decided to set a goal for the essay I found my topic. I did some research and found a way to answer my research question. After this I started teaching myself the stuff I did not know but was required for the essay. Just be careful not to take on to much because you will end up with a lot of math that you need to learn. This happened to me and it took me a long time to finish my essay. Your essay can be connected to medicine. However you need to be more precise. You can prove some kind of formula or derive an expression that you will apply latter in the essay. You will definitely apply math in the real world however you will first need to give proof and reasoning for the mathematics that you are going to be using
9. You realize that a 42% from paper 1 (20%) and 2 (30%), 30% from the IA (30%) and 15% from paper 3 (20%) means 42%*20%+42%*30%+30%*30%+15%*20%=33% (a 3) Instead of 42%+15%+15%=72%? (And a 7 in paper 3 of the sets relations and groups option is actually 42/60 which is 70% or 14% weighted) You have to get an average of 72% to get a 7 (or a sum of the weighted percentages) instead of a sum of 72% in all papers for the unweighted percentage. It's possible that I interpreted your post wrong though, if that's the case I'm sorry, but it does seem strange that you said and which caused my (probably the case) misunderstanding. I meant to say 21% from paper 1 and 21% from paper 2 out of a maximum of 30% for each which is 42% for the final grade 84 marks out of 120 is 70% of the paper and 70% out of 30% is 0.7*0.3=0.21 or 21% When I said 30% form the IA and paper 3 I meant that you can get 15% out of a maximum of 20% from each which gives 30% for the final grade. in this scenario you would end up with 72% for the final grade. 0.7*0.3 +0.7*0.3+ 0.15 +0.15=0.72 or 72% Paper 1(30%) Paper 2 (30%) Paper 3(20%) IA (20%) Sorry if if previous post was confusing. I just read it and you can definitely interpret it in different ways
10. Stronger candidates might have problems with the 8th, 9th, 11th under a) and the 13th question in my opinion. This all depends on the individual and I don't think that a candidate that is aiming for a 7 will fail to get any marks in these questions ( since you failed to solve 2 questions). Even if you fail to gain any marks in them you will end up with 84 marks out of 120. This is 70% of the entire paper and 21% for the final grade. The paper is definitely harder than usual. I would say that it's somewhere around may 2011 TZ1 HLP1 difficulty. I feel that the specimen paper is a little harder . Considering the grade boundaries for the may 2011 paper and the entire examination https://www.dropbox.com/s/yyx7gy19b521rlm/marks%20range.jpg https://www.dropbox.com/s/7kxpv6iftangnz4/full%20marks.jpg Even if you get 42% from paper 1 and 2 and 30% from the IA (15%) and paper 3 (15%) you would still do fine and be able to get a solid 6 or a 7 with 72%. This is in my opinion the worst case scenario for someone who is aiming for a 7. And I don't think that it's that hard to get at least 8% more for a solid 7 if you can manage to do this much. If you are doing sets, relations and groups it would be crazy to get below 18% or 17% from paper 3. I personally found 11 a) to be challenging since I had never done this kind of substitution. The 13th a) took me some time however I did manage to do it under the time limit. The 8th and 9th were one of the harder ones on the paper but people who have strong reasoning will solve them quickly. The rest are very similar to past paper questions and someone who has done a lot of past papers should not have problems with them. Regarding question 9 I am skipping the differentiation the only way to do this is by inspection derivative of f(x)= e^x -ex^(e-1) => e^x -ex^(e-1)=0 to find roots =>e^x =ex^(e-1) =>e^(x-1)=x^(e-1) => x-1=(e-1)lnx the questions states that there are only two roots. 1 is an obvious root because ln1=0 hence LHS 0 and 1-1=0 hence RHS=0 e is also an obvious root because lne=1 If this was on paper 2 you can easily do this by using gdc however there is a hint here and the roots are way to obvious when you simplify the equation You can sketch the graph by first finding the max and min. You can do this by testing whether the slope is negative or positive on each side of the points. This will tell you where the function increases or decreases. You can find the zero by substituting x=0 in the original equation. The sketch is easy with this info. The last part follows from the graph you see that all values for f(x) are larger than 0 => f(x)>0 => e^x -x^e>0 => e^x =x^e let x= pi and you prove what is reacquired by substituting
11. ## Will I get penalized for not giving my answers to 3 significant figures on probability questions

My main concern is when I am working with binomial, Poisson and normal distribution. Sometimes( only twice out of a lot of problems solved) rounding a number to 3 significant figures might produce an incorrect value on my calculator. Will it be fine if I work with more significant figures during the entire question but give my final answer to 3 significant figures? I know that this is a silly question but my school never covered this and I don't want to lose accuracy marks.
12. ## Will This kind of mistake cause me to loose a grade in my EE

I forgot to put pi/2 in there. Everything continues perfectly and the researched question is answered. Basically this has no effect on the rest of the essay it might confuse someone because it is missing. I feel a little better now. Thanks guys I hope the examiner misses it or at least takes it easy on me
13. ## Will This kind of mistake cause me to loose a grade in my EE

In the case that the examiner thinks that this is a major mistake. How much do you think it will cost me?
14. ## Will This kind of mistake cause me to loose a grade in my EE

I took a math EE and I already submitted it to my coordinator about a month ago. For some reason I decided to read it again and I found 2 mistakes. I wrote km^7 instead of km^2 and There was an equation where I had to factor out pi/2 from 3 terms but forgot to multiply one of them with it in the previous equation. I am really worried because I am evaluating the arch length of an ellipse. This is beyond that options and further maths. I have read in the criteria that we should not try to tackle mathematics we can not understand. I am worried that it may seem like that to the examiner because of the second mistake. My mentor also didn't write any comments on the yellow cover. This also worries me because when you add it with the mistakes it might suggest that this is not my own work. I maid sure that I wrote sentences for more complex steps to explain everything. Should I be worried?
15. try writing about pascal's rule
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