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Math SL Paper 1!


Klauu

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I was very pleased with the paper 1 examination; the section B questions seemed fairly straightforward, as well as those in section A. I managed to complete more or less all of the questions, but struggled with the question involving the products/sums of roots.

 

The integral involving the tangent substitution was tricky, I couldn't figure out how to arrange it only in terms of tangent, but had an epiphany in the last 10 minutes and managed to complete the question. 

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My exam was for TZ2 and omg!!!! Some questions weren't to bad but the last question was such a pain, the probability one with the 10$ and winning... that one i coudnt figure out. I did write something involving the expected value so im hoping that i got some points. There was some other question i coudnt figure out, cant remember it. My brain is fried from paper 1 and 2. Cant wait to discuss paper 2 and omg chem exam tomorrow, time to study!

I actually solved it in a really simple way. I don't think I'll get full marks though. What I did was I thought about it as if she had played 10 times, then she would have paid $100 as it costs $10 to play. Because the chance of getting the black ball (the one she needed to get money back) was 0.4 it means she would have picked 4 black balls. Because it was a fair game, she would have got her $100 back from those 4 black balls which you can simply calculate by 100/4 = 25. So every time she picks a black ball, she gets $25. 

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My exam was for TZ2 and omg!!!! Some questions weren't to bad but the last question was such a pain, the probability one with the 10$ and winning... that one i coudnt figure out. I did write something involving the expected value so im hoping that i got some points. There was some other question i coudnt figure out, cant remember it. My brain is fried from paper 1 and 2. Cant wait to discuss paper 2 and omg chem exam tomorrow, time to study!

I actually solved it in a really simple way. I don't think I'll get full marks though. What I did was I thought about it as if she had played 10 times, then she would have paid $100 as it costs $10 to play. Because the chance of getting the black ball (the one she needed to get money back) was 0.4 it means she would have picked 4 black balls. Because it was a fair game, she would have got her $100 back from those 4 black balls which you can simply calculate by 100/4 = 25. So every time she picks a black ball, she gets $25.

I got the same answer, but I have no idea how it can be worth 10 points!

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I did TZ1. The majority of it was fairly easy for me, surprisingly.

....and then I got to question 10 and wanted to rip my exam paper. :help:

 

Did anybody in TZ1 get it? It was the one with Bob and Ann playing some stupid game with 8-sided dice. :dash:

I did as well, at least for a good five minutes of staring at the paper trying to figure what part e was asking

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I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

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I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

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I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

I did the exact same on accident. I was rushing it because I left it till the end, hope they do because I need those extra 1 or 2 marks. :)

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what about the one of integrating lnx/x ? 

It was ( lnx^2 / 2 )

 

 

But like... that was something like integration by parts?

 

yes i guess, it was quite hard though, i missed out on the (/2) part of the answer because I didn't notice. I checked the answer after the exam and it was (lnx^2 / 2)

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what about the one of integrating lnx/x ? 

It was ( lnx^2 / 2 )

 

 

But like... that was something like integration by parts?

 

yes i guess, it was quite hard though, i missed out on the (/2) part of the answer because I didn't notice. I checked the answer after the exam and it was (lnx^2 / 2)

 

Did you use substitution method?

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what about the one of integrating lnx/x ? 

It was ( lnx^2 / 2 )

 

 

But like... that was something like integration by parts?

 

yes i guess, it was quite hard though, i missed out on the (/2) part of the answer because I didn't notice. I checked the answer after the exam and it was (lnx^2 / 2)

 

Did you use substitution method?

 

I used the chain rule in reverse... Because lnx/x is simplified to lnx * 1/x, and since the derivative of lnx is 1/x the 1/x must have come from the differentiation of lnx. Hence, if you take 1/2(lnx)^2, the chain rule will give you lnx/x... at least how I did it..

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I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

I think you get error carried forward or something

what about the one of integrating lnx/x ? 

it was quotient rule

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I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

I think you get error carried forward or something

what about the one of integrating lnx/x ? 

it was quotient rule

 

 

 

I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

I think you get error carried forward or something

what about the one of integrating lnx/x ? 

it was quotient rule

 

That's what I did. I got some rubbish answer though (I honestly don't remember what it was). But yeah (I am also TZ1).

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I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

I think you get error carried forward or something

what about the one of integrating lnx/x ? 

it was quotient rule

 

 

 

I did TZ2 and messed up the expectation question... I wrote that there was 0.4 chance of getting 0, and 0.6 for getting k dollars... if all of my working is correct, does this count as misread - will I lose only 1 mark of all of them?

I think you get error carried forward or something

what about the one of integrating lnx/x ? 

it was quotient rule

 

That's what I did. I got some rubbish answer though (I honestly don't remember what it was). But yeah (I am also TZ1).

 

I used substitution, but I think I got the same answer :D 

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Notice how both timezones had a tough probability question? :P

I wouldn't say our TZ2 was nearly as hard as TZ1. All we had to do was divide 2 numbers, and get the answer. It was recognizing that the question was a expected value question that made it confusing. TZ2's derivative and vector questions were the real challenges.

I had trouble with question 7, didn't knew what to do. Also with derivates I didn't knew that f^3 was the third derivate :/ so I did it like f(x)^3 haha what a shame. Vector was really easy to me but question 10 was like hell

 

 

Hahaha I did the same for f^3 and when i came out i was like *facepalm* thats like 4 marks bye-bye. Glad I wasnt the only one because i seriously thought the examiner was going to have a laugh when he/she saw that :P Rest of it went pretty well... I think I got everything including 10 but lets see :D

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