Having been tutored by Nav for 3U and 4U was one of the best decisions I made in my HSC. Nav has a clear and concise way of explaining concepts far exceeding my teachers. For example one of my weakest topics was proofs as I was quite unfamilar with the logic required. In just two lessons I...
This will be my last post, BOS is literally the ultimate form of procrastinating. You feel as though you are doing work yet BOS is simply another form of social media. Its been a fun ride.
The reccurence relation is : C_{n+1}=C_{0}C_n+C_1C_{n-1}+...+C_nC_0 where C_{k} is the kth catalan number.
The general term is: C_n=\frac{1}{n+1}{2n\choose n}
where {2n \choose n} means 2n 'choose' n. It may be worthwhile looking into some basic combinatorics i.e. permutations and...
\cos{x}\cos{y}-\sin{x}\sin{y}=\frac{1}{4}(\sqrt{3}-\sqrt{2})-\frac{1}{4}(\sqrt{3}+\sqrt{2})
\cos(x+y)=-\frac{\sqrt{2}}{2}
x+y=\frac{3\pi}{4}
Since second quadrant.
The main reason is that you need to use transformers for a bunch of appliances (e.g. if your phone charger didn't have a transformer built into it, it is going to explode if it gets the 230V coming from the plug point). Transformers only work for AC current and not DC so of course AC is preferred.
I don't think your right for ii. If we have a graph of f(x) and want to sketch |f(x)| all parts of the graph below the y axis is flipped along the x axis. Hence the left branch of the hyperbola now becomes completely positive as shown:
from i we found that the poi is (-2,2) hence the region...
There is a complicated process the marks go through and there are many guides here on BOS you can look up, but basically your raw mark gets 'moderated,' to a moderated mark. For example those that are getting a final mark of 90 in 4U didn't really get a 90% raw in 4U and actually got around 70s.