Maths Methods 3/4 Help Thread 2011

[Panicmode]

nopes you solved it the way i did
except i forgot about u = -1

and that is an interesting way of factorising
i was always bad at factorising

Lol, really... hmmm. How did Kilbaha solve it? This seems the most logical way to me.

[nacho]

Has anyone done MAV 2008 exam 2?
Am I the only one that found it hard/tedious ?

[BlueSky_3]

Hard? Nah ...... but tedious? Yes. And also very similar to VCAA 2007 Exam 2 

[paulsterio]

Methods exams aren't usually hard, they're only tedious and long-winded

[nacho]

what just happened here:

because 2sin(x)cos(x) = 1/2
therefore sin(2x) = 1/2
??

[Greatness]

what just happened here:

because 2sin(x)cos(x) = 1/2
therefore sin(2x) = 1/2
??

dont worry about it, it's a double angle formula. you wont need it in methods

[b^3]

EDIT: If you want it anyway.
It's the double angle formula.
sin(2x)=2sin(x)cos(x)
You know that sin(x+y)=sin(x)cos(y)+cos(x)sin(y)
so sin(x+x)=sin(x)cos(x)+cos(x)sin(x)
=2sin(x)cos(x)
so sin(2x)=2sin(x)cos(x)

[nacho]

when you get quesitons like:
".. h(t) = 2sin(3t/pi)
where h= height of the waves at the beach, t = time after 6am

and its like, "the only time it is safe to swim is when the height of the wave is less than 1.5m

'over a 24 hour period, between what hours is it safe to swim?'

do u graph it on your CAS? wouldnt it be like retarded finding the solutions?

I always try and use identities to solve it, is that what you do?

also,
'consider the functional equation k(t+pi) = k(t). show that the function with the rule k(t) = cos(2t) satisfies this functional equation. Give reasons for your answer.



to do part b) ? Derp

[BlueSky_3]

Cas or non-CAS ?

[knightstarr17]

hey guys sorry to interrupt but I was just wondering what I should. The problem at hand is, I have complete 40+ (Exam 1 &2) methods papers but still fail to get 40/40 for exam 1, I average around the 34-38/40, I do not know if I should do more exams, or just expect the fact I wont get 40/40. Any help/advice will be appreciated    

[homosapiens]

hey guys sorry to interrupt but I was just wondering what I should. The problem at hand is, I have complete 40+ (Exam 1 &2) methods papers but still fail to get 40/40 for exam 1, I average around the 34-38/40, I do not know if I should do more exams, or just expect the fact I wont get 40/40. Any help/advice will be appreciated    

Go through what you've done picking out common errors. That way, you can fix them up and hopefully get 40/40 next time (:

[knightstarr17]

After Most Exams I go over my mistakes and actually re do the questions I got wrong. I guess I will just go over all the mistakes from all the papers. Also should I push to finish quicker so I will have a longer period of time to go over my exam to fix up the little mistakes? What is the recommended time to finish the exam? Thank you for you help

[Hamdog17]

Is it sufficient to write "Solve f(x)=4 for x over the domain R" in order to get the methods mark in a question?

Also if a normal distribution question to asked you to find a probability given a std dev and mean and was worth more than one mark what would you write?

Would this be okay?

std dev=90, mean=120, x1=110, x2=200 then just state the Pr

[ben_sebastian4]

From the VCAA 2010 exam 2

Victoria hears that another company, Shoddy Ltd, is producing similar statues (also classified as Superior or
Regular), but its statues are entirely made by machines, on a construction line. The quality of any one of Shoddy’s
statues is independent of the quality of any of the others on its construction line. The probability that any one
of Shoddy’s statues is Regular is 0.8.
Shoddy Ltd wants to ensure that the probability that it produces at least two Superior statues in a day’s production
run is at least 0.9.
e. Calculate the minimum number of statues that Shoddy would need to produce in a day to achieve this aim

When i put it all into my calculator i keep getting 12 when the answer is 18. Im doing 1 - ((PrX=0)+(PrX=1))
Any suggestions

[homosapiens]

After Most Exams I go over my mistakes and actually re do the questions I got wrong. I guess I will just go over all the mistakes from all the papers. Also should I push to finish quicker so I will have a longer period of time to go over my exam to fix up the little mistakes? What is the recommended time to finish the exam? Thank you for you help

Yeah it's best to leave ~10 minutes at the end to check, how long do you usually take to finish a paper? If not after you finish every question, just reread the question quickly and skim through making sure you've answered what it asked with units etc, so you're checking as you go and aren't as pressed at the end and have the question fresh in your mind as well as what you've done. If you've got time at the end go through and check again with a fresh mind, you might see things you didn't pick up the first time.