VCE Methods Question Thread!

[Jesse_ando]

pics diddnt show up on my post, i'll attach them here again

[StupidProdigy]

Hi StupidProdigy, just a quick question, do you know why the VCAA answer includes the square bracket around the 9? As the question states 'strictly decreasing', the point where x=9 the curve is stationary, not increasing nor decreasing. It's question 1 of section 2 of 2009 E2 (i've included the pics)

I prefer to avoid thinking about the gradient to an extent for strictly increasing/decreasing questions-I think it is more intuitive to think about things in terms of the height of the graph (y values). Yes the gradient is 0 at x=9, however the curve is only equal to the y value at x=9 once which is obviously at x=9, therefore it is our starting point (inclusive) for strictly decreasing. So because there are no other values as high as f(9) the condition that any other f(x) output is less than this is satisfied. So f(x) is strictly decreasing from 9 (inclusive) to infinity because the outputs of f(x) will always be lower in height than f(9). I find this hard to verbalise/explain clearly so anyone else feel free to

[nadiaaa]

If I need to keep saying things just tell me, I'm more than happy to try and reword or more concisely convey what I'm saying

Thank you!!!! I finally understand, yeah when i zoom in and i can see everything you're saying, also so the ti can sketch graphs with two variables like d & t? Thats so cool, before i was puting t as zero and t as 5 and i think thats why the graph never showed up..
Once again thank u!

[Butterflygirl]

Can someone explain how to do the questions attached?

For the probability one, I thought we use p=2/3? not 1/3? but I'm not sure how to choose the correct p value.

For the attachment, how do we know that the area under the line from 0 to p is 25/8? Isn't that only the actual shaded region?

Help is highly appreciated! Thankyou!

[MightyBeh]

Can someone explain how to do the questions attached?

For the probability one, I thought we use p=2/3? not 1/3? but I'm not sure how to choose the correct p value.

For the attachment, how do we know that the area under the line from 0 to p is 25/8? Isn't that only the actual shaded region?

Help is highly appreciated! Thankyou!

Solutions attached. What exam is this from? I vaguely remember doing these questions.

[godsonsamuel888]

Hey guys I need some help.
I am trying to do this on the CAS, but its giving me these weird answers?? am I typing in the syntax incorrectly?

and my CAS is running version 4.2.0532

[halo]

Hey guys I need some help.
I am trying to do this on the CAS, but its giving me these weird answers?? am I typing in the syntax incorrectly?

and my CAS is running version 4.2.0532

Hey! You should try defining f(x) for its domain (ie define f(x)=cos(2x)| 3pi/4 <x< 5pi/4) before antidiffing, and then just type in exactly what it says in the solutions except instead of cos(2x), type in f(x), which would then give you their answer I think.

[godsonsamuel888]

Hey! You should try defining f(x) for its domain (ie define f(x)=cos(2x)| 3pi/4 <x< 5pi/4) before antidiffing, and then just type in exactly what it says in the solutions except instead of cos(2x), type in f(x), which would then give you their answer I think.

Ohh ok thanks. and yess it worked.

[MB_]

Hey guys I need some help.
I am trying to do this on the CAS, but its giving me these weird answers?? am I typing in the syntax incorrectly?

and my CAS is running version 4.2.0532

I don't have a TI-Nspire but it looks like you're getting a general solution so you need to set the restriction of \(\frac{3π}{4}≤a≤\frac{5π}{4}\)

[godsonsamuel888]

I don't have a TI-Nspire but it looks like you're getting a general solution so you need to set the restriction of \(\frac{3π}{4}≤a≤\frac{5π}{4}\)

Thank you!!! 

[The Usual Student]

can someone help me out here?

A ladder is trying to reach behind a 1.2 m fence to reach a wall 0.5m behind the fence. Find the minimum length of the ladder required to reach the wall.

[eru]

Can someone please explain why they've used 2 as their z value and not 1.96? ty

[natdogg]

Can someone please explain why they've used 2 as their z value and not 1.96? ty

Question specifies 2 standard deviations!
If it said 95% confidence interval, you would use 1.96!

[MandhreeE]

hi guys this is a bit of a silly question but i always get confused. When we square root something we have to remember +- but then on some occasions we just take the +... is this correct? if so when do we know when we have to have +- and when we have+. sorry i'm not sure if i'm making sense.
Thank you!!!

[MB_]

hi guys this is a bit of a silly question but i always get confused. When we square root something we have to remember +- but then on some occasions we just take the +... is this correct? if so when do we know when we have to have +- and when we have+. sorry i'm not sure if i'm making sense.
Thank you!!!

When we take the positive root the question will have a restriction such as x>0 otherwise we state both answers. Hope this helps