VCE Methods Question Thread!

[keltingmeith]

Thank you so much!! However I don't understand b :/

Sorry - I forgot to change it into a Z halfway through - let me go and fix that.

Also, the working is based on the fact that:



Which is by the symmetry of the normal distribution.

[Kaleidoscope]

Thank you so much!! However I don't understand b :/

Have a read of this - example 6.6 is pretty similar to your question.
https://www.inkling.com/read/business-statistics-jaggia-kelly-1st/chapter-6/solving-problems-with-normal

[speedy]

How does one even do these... 

I know I'm late, but may as well post my solution. I would always draw the graph for these types of questions

Spoiler

Edit: spoilers aren't working for me, so if that's the same for everyone: http://i.imgur.com/jQo4AmW.png ; http://i.imgur.com/Q7YWZ7i.png

[keltingmeith]

Oh gosh. Can't believe I have done so much probability without knowing the foundations
 
Also, if you were asked to find the area of a modulus function.
Eg. Area of abs (sin (x)) from (idk) x= 0 to x=2pi

Would you split it into two hybrid functions? Where one is the sin(x) and the other is -sin(x).. find x-ints etc. then integrate?

Or would you use symmetry properties and find the first x-int and multiply by however many 'loops' it goes through?

Which way is faster?
*I am sorry if my question doesn't make sense, can clarify if needed*

You COULD split it into the hybrid functions, but you've recognised that the area is symmetrical, so there's no point. Your second method is easier, faster, tends to less mistakes AND works. The best four things of any method!

[Reus]

You guys are life savers.

[M_BONG]

Also, Euler do you recond we need to know about limits?

I remember in Year 11 we did something like

If the limit is the same from both the left and right side, the graph is continuous or something?

Also, could they test diff by first principles in exam 1?

[keltingmeith]

Also, Euler do you recond we need to know about limits?

I remember in Year 11 we did something like

If the limit is the same from both the left and right side, the graph is continuous or something?

Also, could they test diff by first principles in exam 1?

You DO need to know if a graph is continuous, I don't think you need to know the formal definition (which is what you're referring to - and is right, btw)

Yes, they could easily ask you that in exam 1. Remember, diffing by first principles and diffing the "normal" way give the same result, so you can very easily check your answer to see if you're right.

[Reus]

What's integration by inspection? :/ 

[Blondie21]

What's integration by inspection? :/ 

It's when you do the integral thing and sub in numbers ... Like when you've got that integral sign and those numbers on the top and bottom... LOL worst explanation ever

[keltingmeith]

What's integration by inspection? :/ 

I'm assuming it's this:

[Reus]

I'm assuming it's this:

How'd you do that .__.
Can you sit my exam tomorrow pls?

[Rishi97]

The reason we do this, is because we cant antiderive functions that have product rule or quotient rule. SO we have to derive a function similar to it. Look at 2013 vcaa exam 1 (I think q9) the long one. That's integration by recognition/inspection.
Relax Reus you will be fine

[jessss0407]

quick question: for the exam, if we were to do separate working out to check our answers - do u think it'd be okay? is it not recommended or..?

[Blondie21]

Oh my bad

[keltingmeith]

How'd you do that .__.
Can you sit my exam tomorrow pls?

Here's a pretty cool thing:



Which may explain what I did.

If you just rote learn the steps I did, you'll be fine for any integration by recognition question (I'd say there's a good chance of them throwing one again after last year - every integration thing from last year was done poorly, so I'd be surprised if at least one of them isn't repeated)