3U Maths Question Thread

[RuiAce]

Hi, how do I solve q24 and 25 for permutations? Thank you in advance

I found the answer to Q25. Will get back to Q24 if nobody beats me to it

[RuiAce]

Hi, how do I solve q24 and 25 for permutations? Thank you in advance

Essentially the alternating roles forces two splits to occur in the analogy.

[key to success]

Could someone help plz. Thanks!

[RuiAce]

Could someone help plz. Thanks!

Which part are you having trouble with?

[key to success]

Which part are you having trouble with?

aii- how do we sketch the function and also bi, please.
Thank you very much )

[RuiAce]

Which of course, you should know how to sketch because it's just a horizontal line. Just remember that it's only defined on \( 0\leq x \leq 1\), so you have endpoints.

The answer to b) i) is just \( \binom{7}{k} 2^{7-k}3^k \) using your reference sheet.

[key to success]

Which of course, you should know how to sketch because it's just a horizontal line. Just remember that it's only defined on \( 0\leq x \leq 1\), so you have endpoints.

The answer to b) i) is just \( \binom{7}{k} 2^{7-k}3^k \) using your reference sheet.

Thank you so much- that helps heaps!

[Mate2425]

Hi does anyone know how to derive the differnt parametric forms of the parabola in case you forget them in a test?

Thank you.

[envisagator]

Hi does anyone know how to derive the differnt parametric forms of the parabola in case you forget them in a test?

Thank you.

Parametric forms of the parabola are given in the formula sheet.

[RuiAce]

Hi does anyone know how to derive the differnt parametric forms of the parabola in case you forget them in a test?

Thank you.

Parametric forms of the parabola are given in the formula sheet.

Yeah this for the most part.

For anything that's not on the reference sheet (e.g. point of intersection of the tangents) you will need to derive it, unless it's explicitly given in front of you in the exam.)

[Mate2425]

Hi everyone need help with Q7 MC for HSC Paper 2016. How do you go about when you have two parts in the same question?
http://educationstandards.nsw.edu.au/wps/wcm/connect/756b83c4-d51a-4033-ae36-ff7cd39d4369/2016-hsc-maths-ext-1.pdf?MOD=AJPERES&CACHEID=ROOTWORKSPACE-756b83c4-d51a-4033-ae36-ff7cd39d4369-lCkVKC5

Thank you!

[RuiAce]

Hi everyone need help with Q7 MC for HSC Paper 2016. How do you go about when you have two parts in the same question?
http://educationstandards.nsw.edu.au/wps/wcm/connect/756b83c4-d51a-4033-ae36-ff7cd39d4369/2016-hsc-maths-ext-1.pdf?MOD=AJPERES&CACHEID=ROOTWORKSPACE-756b83c4-d51a-4033-ae36-ff7cd39d4369-lCkVKC5

Thank you!

[beeangkah]

Hey I just tried this question and did the differential twice to get acceleration, then equated it to 0 and solved for t.
I got a negative value for t, but when I subbed it back into the velocity equation it worked out? I got 52 for the answer.

[RuiAce]

Hey I just tried this question and did the differential twice to get acceleration, then equated it to 0 and solved for t.
I got a negative value for t, but when I subbed it back into the velocity equation it worked out? I got 52 for the answer.

If you set \( -104 \sin (4t+\alpha) = 0\), which isn't really best done with an ASTC approach, you should be using boundary angles and realising that \( 4t+\alpha =..., 0, \pi, 2\pi, 3\pi, 4\pi,...\) and so on. As you say, if you take the solution \( 4t+\alpha = 0\), you get something negative for \(t\). So you only consider the ones starting from \(\pi\).

That will keep the value of \(t\) positive.

[Mate2425]

Thank you so much Rui, i now understand clearly. On a side note could you also please explain what the phase does in the normal displacement of a particle formula because i am struggling to understand where/ why we use it.
Thannnkkkks!