I wrote something like: they kill the micro organisms that spoil the food and used as antioxidants to prevent the oxidation of oils which helps preserve the food. Don't think I described it though :/
re: HSC Chemistry Marathon Archive
1. Nitrates can be tested for using the brown ring test, where iron sulfate is added to the water sample inside a test tube, then sulfuric acid is slowly added. If a brown ring forms, then nitrates are present. Phosphates - ammonium molybdate test, where you...
oh yeah that's true in that sense -.-
I can't really see how I can improve THAT much in English though.
I kinda meant: do you think it's better to improve a few marks in English or a few marks in my other subjects?
sorry about the confusion :/
My school did the physics independent paper as well. Our teacher said that the marking guidelines were pretty poorly done for a few questions (e.g. that it doesnt deserve a 3/3 but rather a 2 or a 1) and I really have to agree there. If i recall, that slingshot question was one of them. So they...
The way I saw it was that most people would probably not focus as much after the trials, so it would've been better to finish the course before then. But it probably is a better idea to take it easy and get through the content thoroughly.
It looks like we're pretty behind.
Almost half-way through mechanics and still have harder 3u and graphs to go.
Definitely won't be finishing 3u course before trials and probably not 4u either :/
Re: HSC 2013 3U Marathon Thread
You could consider the graph of y=\sqrt{a^2-x^2} which is just a semi-circle.
y_{1}=\sqrt{a^2-b^2}
\int_b^a \sqrt{a^2-x^2} \ dx=Area(sector)-Area(triangle)
=\frac{1}{2}a^{2}\theta - \frac{1}{2}b\sqrt{a^{2}-b^{2}}...
I know the answer but I just can't seem to get it.
Please help!
Question is found in Yr 11 Cambridge Maths 3U book, Exercise 1E, Q16 (pg 12)
Simplify (1+a)^2/[1+(a/(1-a+(a/(1+a+a^2)))]
This is the image of the question.
Any help is appreciated. Thanks