# Search results

1. ### Permutation and combinations, confusing question

Let there be 5-2z stars and 1 bar (since we want to split 5-2z into two parts the number of stars in each part is x and y). We can arrange these in {{6-2z}\choose{1}}=6-2z ways (including the extra bar we have 6-2z objects needed to be arranged). Now all we have to do is sum this up from z=0-2...
2. ### Delta English tutoring is very exclusionary

To be fair the whole thread was based around recommendations for jkjkjk so it would be odd for him to advertise to a random commenter rather than the guy who made the thread.
3. ### Delta English tutoring is very exclusionary

I read in another thread that the reason delta is so expensive is because they pay their tutors top dollar because they all state ranked?
4. ### Vector Help

Direction is zero? Thats clearly wrong which textbook are you using?
5. ### Vector Help

Even easier as the vector points 5 units up at an angle of 90 degrees to the positive x-axis.
6. ### dropping eng ext 1

I think you already have a good grasp of the pros and cons of dropping the subject. Imho I think if you are doing a subject solely for 'a safety net,' and 'high scaling,' then it's not wise to keep it. You clearly aren't enjoying it from the looks of things, nor do you have the time to do it. I...
7. ### Integration help

Its quite easy C_n outputs C_n
8. ### Integration help

Just a pedantic correction, it may be better to name your constants C_1 and C_2 rather than both C as this implies they are both the same.
9. ### Series prerequisite for Proof by induction?

Nope no need for AP and GP, but you definitely need to understand what a 'sequence,' and what a 'series' is. It may also be wise to understand how the number of terms of a series and the last term of a series can both depend on a variable. For example the series: 1^2+2^2+3^2+...+n^2 has n terms...
10. ### HSC 2018-2019 MX2 Integration Marathon

Using the identity: \sin\alpha\cos\beta=\frac{1}{2}\left(\sin{(\alpha+\beta)}+sin{(\alpha-\beta)}\right) \int_{\frac{1}{4}}^{\frac{1}{2}}\sin\left(x^{x}+\ln x\right)\cos\left(x^{x}-\ln x\right)\log_{2}\left(ex\right)dx...
11. ### Tricks in permutation and cominations

Half the total ways are when S is to the left of H and half are when S is to the right of A. So simply work out the total number of ways of arranging the letters in general then divide by 2 (what Bianca did).
12. ### Integration Question

Literally subsititute in the point so: 2\sqrt{3}=2sin\left(2 \times \frac{\pi}{6}\right)+C and solve for C
13. ### Hey man don't let that thread get to you, you are clearly capable but I think being humble goes...

Hey man don't let that thread get to you, you are clearly capable but I think being humble goes a long way!

Breaking bad
15. ### curve sketching

Yes you should dot them or at the very least label y=0 or x=0 as an asymptote.
16. ### Tricks in permutation and cominations

Give an example.
18. ### \$10 HSC CHEMISTRY (93 HSC/95 Trials/1st in School/98.40 ATAR 2020) DETAILED (86-pg PDF) FULL STUDY NOTES *NEW SYLLABUS (2019)*

You should probably put some sort of copyright disclaimer if you haven't done so, or else ppl may distribute or resell.
19. ### Tricks in permutation and cominations

Whilst I agree there is a lot of variation most of perms and combs is formulaic just like the rest of the syllabus (by most I mean like 80% whereas 20% is unknown or has a trick). You will find a lot of questions use the same trick whereas a few require you to try something new.
20. ### HSC Marks Required

Yes lol, it's based of ppl submitting their raw marks they gained from nesa.