# Recent content by PC

1. ### Thoughts on standard maths?

Wow. That's quick.
2. ### Thoughts on standard maths?

Thanks for this. You're right on Q30. I drew a new diagram and left out the track CG as well as the track CH which was the one that was closed. In Q42, you're right in that interest is only paid in 5 of the first 6 years, but the annuity table takes care of all that, so you still have to choose...
3. ### Thoughts on standard maths?

Q1 = 185, Q3 = 194, IQR = 194-185 = 9 Lower outlier < Q1 - 1.5 x IQR < 185 - 1.5 x 9 < 171.5
4. ### Thoughts on standard maths?

Exam paper My quick answers were: 1. A 2. B 3. B 4. C 5. D 6. C 7. D 8. B 9. A 10. A 11. C 12. D 13. C 14. B 15. A 16. 1072 cm3 17. 16 cm 18. (a) 6:5:8 (b) 180 runs 19. Yes, an outlier 20. 500 times 21. 8% 22. 41°5’ 23. (a) 0.98 (b) Strong positive correlation (c) 147 cm 24. 6.5 km 25. 8/17...
5. ### Thoughts on standard maths?

The golden rule is not to round off until the final answer. I kept the BAC to 10 sig figs, ended up with a final answer of 6:23 am. But in that question early rounding will probably be accepted if all the working is shown.
6. ### Thoughts on standard maths?

Nothing too controversial on this paper. Students who learned their course could answer every question. Interesting to see if people found it tight with time. Q18 might have tricked a few people if they added the 19 and 36 to try to find the total score. Yes, I had to think about the receipt...

8. ### General 2 paper

And worked solutions are here. Usual disclaimer - all care taken, no responsibility for errors, but I will try to correct them if you spot any.
9. ### 2 unit paper

Yeah, I did it that way too, but it wasn't as much fun. By the way, the method of expanding xn - cn IS part of the 2 unit course. It's part of the introduction to calculus and is usually done with limits and differentiating from first principles. Questions on first principles are rare, and so...
10. ### 2 unit paper

... and here are some worked solutions. The usual disclaimer applies. It would great if you could point out any errors.
11. ### Someone explain how bad is general maths scaled?

The scaling changes every year. If the paper is relatively easy (as last year's was), then it's naturally harder to get a higher scaled mark. If the paper is harder, then less people will get the high raw marks, so scaling isn't so harsh (so to speak). Look. The bottom line is that you have to...
12. ### Scale Down?

Well this is all well and good, but the way that this year's HSC marks will be scaled will vary from the way that last year's HSC marks were scaled. A few things to keep in mind. 1. A quick glance at the table shows me that unless you got 100% in 2 unit Maths, every mark got scaled down in that...
13. ### Some Questions from AIMO 2009

I didn't do it. I'm just trying the questions for fun (possibly not the best word).
14. ### Some Questions from AIMO 2009

Here are two questions which I'm stuck on. You might like to have a go, and perhaps post the solutions. 8. In ∆ABC, angle ABC = 138° and angle ACB = 24°. Point D is on AC so that angle BDC = 60° and point E is on AB so that angle ADE = 60°. If angle DEC = x°, find the value of x. 9. Let...
15. ### Depreciation

S = V0(1 – r)n We need S = 1000, V0 = 6000 and r = 33% = 0.33 S = V0(1 – r)n 1000 = 6000(0.67)n Divide both sides by 6000 1/6 = (0.67)n Now a number of ways of going from here. 1. Guess and check (or trial and error) 2. Use logs 3. Use solver function on graphics calc Let's use...