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How was Math HL Paper 1?

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Well, if you took TZ2, the section B last question was just pure hell. Even my teacher said majority of students would have not solved it.

 

BTW, I think this topic should be moved to the exam discussion

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Just now, bb8-m8 said:

You mean the complex number question with w^7+w^6 etc.?

Yea. The other two questions on section B was ok, but I just panicked when i saw that question. My teacher showed me the solution and realized that I could have solved it if I acted all calm. 

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1 minute ago, Seung Hun Han said:

Yea. The other two questions on section B was ok, but I just panicked when i saw that question. My teacher showed me the solution and realized that I could have solved it if I acted all calm. 

Yeah, what is wrong with the last question. This is the first time I feel so hopeless dealing with complex numbers. I mean the first few parts were ok. When they asked to deduce that the conjugate of a equals to the other multiples of omega, it took me 10 min to actually deduce it. Then comes even a harder question which is to determine b and c. b I calculated to be 1 by the sum of root but c, how do you actually even calculate it ??? 

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1 minute ago, Haitham Wahid said:

Yeah, what is wrong with the last question. This is the first time I feel so hopeless dealing with complex numbers. I mean the first few parts were ok. When they asked to deduce that the conjugate of a equals to the other multiples of omega, it took me 10 min to actually deduce it. Then comes even a harder question which is to determine b and c. b I calculated to be 1 by the sum of root but c, how do you actually even calculate it ??? 

When I solved section A, I thought, "Hmm... some questions are tricky, but it's generally ok.." When I saw first two questions of Section B I was like "Ok... If I don't make any stupid mistake, I can nail this!" When saw the last question, I shivered a lot. When I saw past grade boundaries for math HL, 7 lower boundary was like 83~85/120, which means that almost most of the good math students will do considerably poorly in paper 1. I am just counting on paper 2 that I did today. I know we are not allowed to discuss the content, but how did you do in math paper 2 (If you have already taken the test)

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Just now, bb8-m8 said:

I thought Section A in P1 was pretty hard compared to previous exams...

If I remember correctly, there were three questions that I struggled the most. First, the probability question, induction question and the last question of section A.

Even though I didn't finish the induction question, I think I managed to get some marks like 4 or 5 out of 8. I think if I had enough time, I could have solved those quetions, but I think I just totally panicked. 

Is it me or do you also think that TZ2 seems always harder than TZ1 every year? Or am I just biased?

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4 minutes ago, Seung Hun Han said:

When I solved section A, I thought, "Hmm... some questions are tricky, but it's generally ok.." When I saw first two questions of Section B I was like "Ok... If I don't make any stupid mistake, I can nail this!" When saw the last question, I shivered a lot. When I saw past grade boundaries for math HL, 7 lower boundary was like 83~85/120, which means that almost most of the good math students will do considerably poorly in paper 1. I am just counting on paper 2 that I did today. I know we are not allowed to discuss the content, but how did you do in math paper 2 (If you have already taken the test)

Actually, I got most scared of the x= 3cos(2y)+4 question the first time I saw it in the 5min reading time, and wasn't scared of the last Q. But actually it turned out that question about the solid of revolution was much easier than the last Q. 

As for section A, I did struggle a bit, specially when they asked to determine the other solution to the trig equation, what was your answer by the way ?

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1 minute ago, Haitham Wahid said:

Actually, I got most scared of the x= 3cos(2y)+4 question the first time I saw it in the 5min reading time, and wasn't scared of the last Q. But actually it turned out that question about the solid of revolution was much easier than the last Q. 

Yea, with no mistake, I think it was an easy way to get 8 marks. 

3 minutes ago, Haitham Wahid said:

As for section A, I did struggle a bit, specially when they asked to determine the other solution to the trig equation, what was your answer by the way ?

Didn't even bother to solve it especially after spending like 5 minutes to solve induction question. 

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2 minutes ago, Seung Hun Han said:

Yea, with no mistake, I think it was an easy way to get 8 marks. 

Didn't even bother to solve it especially after spending like 5 minutes to solve induction question. 

Yeah, you reminded me of the induction question, It was much tricker than I initially thought when I started with the prove. I kept ending with the following 

6A+6+3(k^2+k) and I wanted to prove that this is divisible by 6 but the problem is this quantity k^2+k. It took me a really long time before I realized that this quantity is actually even for all k. 

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Hi!

I think for the complex number question to find c, you should use the product of the roots alpha and its conjugate, and this should equal c. If you multiplied through you would get some strange powers of w (like to the power of 9), but in fact they were equivalent to the w's where some properties were found earlier. The problem would from there simplify itself quite a bit. I dont remember what I got for c however, but it was something like 3 or 2 I think.

 

Also, how did you guys solve the dh/dt problem? I used the chain rule, and ended up with dh/dt=(2)/(2cos squared(2h)+....)ˆ2. But I'm worried since I didn't use the diameter they gave in the question.

Edited by indimpi

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14 minutes ago, indimpi said:

Hi!

I think for the complex number question to find c, you should use the product of the roots alpha and its conjugate, and this should equal c. If you multiplied through you would get some strange powers of w (like to the power of 9), but in fact they were equivalent to the w's where some properties were found earlier. The problem would from there simplify itself quite a bit. I dont remember what I got for c however, but it was something like 3 or 2 I think.

 

Also, how did you guys solve the dh/dt problem? I used the chain rule, and ended up with dh/dt=(2)/(2cos squared(2h)+....)ˆ2. But I'm worried since I didn't use the diameter they gave in the question.

I really wanted to multiple out the powers of w but I thought that there must be another way cuz that would be a tedious manipulation. Since I needed c for the last part of the question I made the assumption that c was 1 as well. At least I could gain the last 4 marks.  But you got b =1 right ??

I yeah, I think I got the same result. However, as far as I remember there was a dv/dh was π*(3cos(2h)+4)ˆ2 , or maybe I am wrong ?. I didn't need the diameter to find the rest of the question as well. BTW did you get h to be 0 ,π/2 and π for which the second derivative of h with respect to time is zero ? 

Edited by Haitham Wahid

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7 minutes ago, Haitham Wahid said:

I really wanted to multiple out the powers of w but I thought that there must be another way cuz that would be a tedious manipulation. Since I needed c for the last part of the question I made the assumption that c was 1 as well. At least I could gain the last 4 marks.  But you got b =1 right ??

I yeah, I think I got the same result. However, as far as I remember there was a dv/dh was π*(3cos(2h)+4)ˆ2 , or maybe I am wrong ?. I didn't need the diameter to find the rest of the question as well. BTW did you get h to be 0 ,π/2 and π for which the second derivative of h with respect to time is zero ? 

Yes I think so, do not remember it completely but it seems familliar.

I think I forgot 0..... but the rest I got :)

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1 hour ago, bb8-m8 said:

I thought Section A in P1 was pretty hard compared to previous exams...

you are not alone. Paper 1 was cancer. I usually get over 100 for paper 1 ad 2, and now I am expecting a 70-80 for paper 1. I didn't read the questions properly and I lost like 19 marks for the calculus question.... 

 

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2 hours ago, thecsstudent said:

I was TZ1 and did really badly compared to how I usually do but other people in my school said it was fine. I really messed up section A but did mostly okay in Section B I think.

I was quite the opposite. I did so poorly in section B......Like so bad bad bad bad bad :(

 

But paper 2 was fine. 

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For TZ2, Paper one was all good except the finding alternative trig answer question and the second-half of the  very last question. And paper 2 questions were really nice. Does anyone know how to solve that trig question since I thought there is only one unique value for both sinX and cosX between 0 and pi/2 :ppp

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10 minutes ago, Chen L said:

For TZ2, Paper one was all good except the finding alternative trig answer question and the second-half of the  very last question. And paper 2 questions were really nice. Does anyone know how to solve that trig question since I thought there is only one unique value for both sinX and cosX between 0 and pi/2 :ppp

The second solution is 11π/36. 

How I found it is by equating the denominators to get (√3+1)cosx+(√3-1)sinx=2√2sin(2x)

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4 minutes ago, Haitham Wahid said:

The second solution is 11π/36. 

How I found it is by equating the denominators to get (√3+1)cosx+(√3-1)sinx=2√2sin(2x)

Nice thinking, well done :)) I always somehow get wrecked by trigs.. Do u also take physics HL? Think I saw u in the physics forum as well, did u do well on that one? 

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2 minutes ago, Chen L said:

Nice thinking, well done :)) I always somehow get wrecked by trigs.. Do u also take physics HL? Think I saw u in the physics forum as well, did u do well on that one? 

Thank you. This question was indeed tricky! but the idea was to realize that sin(a)= sin(π-a). I wish I could have shown you my approach step by step but just writing the formulas and equations would take a tremendous amount of time. 

I do take physics HL and it went really well :)

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