What ARNT You To Sure About For Tomorrow? (1 Viewer)

[DeanM]

just wondering what parts are everyone stuck on ?? like no matter how many times you study it, you just can get it..
for me its bloody those trig idententies: okay lets see:
sin²x + cos²x = 1
1 + cot²x = cosec²x
tan²x + 1 = sec²x

i think thats them.. i can remember them, but i never no how to use them.. haha
so what about everyone else ???

 

[Kutay]

just wondering what parts are everyone stuck on ?? like no matter how many times you study it, you just can get it..
for me its bloody those trig idententies: okay lets see:
sin²x + cos²x = 1
1 + cot²x = cosec²x
tan²x + 1 = sec²x

i think thats them.. i can remember them, but i never no how to use them.. haha
so what about everyone else ???

Mate for that to make it easier for you just memorise

sin²x + cos²x = 1

then if what to derive the others all u need to do is just divide all by sinx to get the tanx and cosec ones and cos for the yeh so on..... just practice doing that and u will be fine, most of the times u only have to use the sin2x =cos2x = 1 one, they tend to ask the others with combinations with such things as double roots in extention one etc

 

[DeanM]

yea thats a good idea... last yrs one was pretty easy... i think there were 3 marks for it altogether and it was in q8

 

[Jexi]

Trig Identities are fun.

What scares me is 10b. Whic usualy involve everything Like reading the question is such a bum.

 

[DeanM]

yea 10b is an essay... there are so many cautions you need to take cause if you read 1 little thing wrong WHAM! you get it wrong..

 

[Jexi]

I know. "yea 10b is an essay" <-- I thought for a second you said easy. My eyeballs nearly popped.


Yes 10B is sooo out to kill me. Usually it involves thinking too :| I happen to like those monotonous Maths questions where you just apply the formulae or solve the algebraic equations (aka. question 1) WOOT.

 

[esieff]

Or if you wanna get crude about it, which I've found has for some disturbing reason worked for me, think of it this way:

A tanned woman (tan2x) + an upright bodily part (1) = Sex (sec2x)
A cot (cot2x) + an upright bodily part (1) = Cot Sex (cosec2x)

I should try re-writing the entire course like this lol. It'd sure make for an interesting textbook.

 

[Shell]

OMG I DONT GET LOGS!!!!! no matter how many time i try to understand, it doesnt go through.
and probability sometimes stumps me

 

[rama_v]

All those geometry rules, like tests for parallelograms and rhombuses. I hope I can remember them

 

[DeanM]

thats a nice way Hotice...
yea what else i hope they dont ask.. is for us to 'find the area of: rhomus, trapezium'
OR if they said 'find the surface area of...'

i think... off the top of my head area for rhombus 0.5(x X y) or something like that..
and the trapezuim is h/2(a + b) is that correct ??

 

[bEAbEA]

i hate loan repayments

 

[rama_v]

Yep
This will aid my memory
Area formulas
Square: x²
Rhombus: (1/2) * xy where x and y are the diagonals
Trapezium: h/2 (a + b) where h is perpendicular height, a and b are the two parallel sides
Triangle: (1/2) bh
Rectangle: bh
Parallelogram: bh where b is base and h is perpendicular height

Some various properties that may need to be known:

The diagonals of a rhombus bisect the vertex angle and each other at 90 degrees.
Any quadrilateral with diagonals that bisect each other is a parallelogram
Opposite angles of a parallelogram are equal
The exterior angle of a regular n-sided figure is equal to 360/n
The interior angle of a regular n-sided figure is (n-2)180/n
If the opposite sides of a quadrilateral are equal and opposite, then the quadrilateral is a parallelogram

And dont forget the "ratio of intercepts are equal" rule.

Now if they ask for surface areas, u can just differentiate the volume of the solid cause I can't remember the Surface area formulas lol. e.g. for a cylinder
V = pir²h
A = 2 pi r h + 2 pi r² for the two ends

 

[l-mercedes-l]

i believed for a very long time that logs were magical and appeared just to piss me off... but if u remember the few log laws its makes it SO much easier and contrary to popular belief they are not magical and appear for a reason.

Formulas!
if y=a^x then x=log[base a]y

log[base a]y is the same a log[base e]y/log[base e]a {which u can then work out on ur calculator}

hmmm and theres another 3 log laws which i can be bothered to think about. Have done 7hours of maths papers today. which is WAY too much for any natural {or bottle} blondes, in fact ill extend that to ANYONE!

 

[DeanM]

thats one i havent heard for awhile... (2n-4)*90 (sum of interior angles or an n sided shape)

 

[rama_v]

thats one i havent heard for awhile... (2n-4)*90 (sum of interior angles or an n sided shape)

Yeah its good to know it..ive seen it in past hscs

 

[DeanM]

yea i hate load repayments aswell... i ALWAYS seem to screw up the interest rate !!!
can anyone verify:
say a question said 'blah blah 6% compounded MONTHLY'
do you stick it into the foruma P(1 + r/100)ⁿ
BUT because its monthly.. you have to go 6/12/100 + 1 ... am i correct in doing this ??

 

[rama_v]

yea i hate load repayments aswell... i ALWAYS seem to screw up the interest rate !!!
can anyone verify:
say a question said 'blah blah 6% compounded MONTHLY'
do you stick it into the foruma P(1 + r/100)ⁿ
BUT because its monthly.. you have to go 6/12/100 + 1 ... am i correct in doing this ??

yep, that is correct.

 

[word.]

remember:-

1. "ratio of intercepts on transversals passing parallel lines are equal"

2. volume of cone = 1/3 pi r² h

3. add interest before subtracting the monthly/yearly payment in loan repayments

4. similar triangles are your friends

5. know your graphs of secx cotx and cosecx or how to work them out at least

 

[DeanM]

lets use this question for example ( my making this up by the way )

a person puts 1000 every month into an account, the money compounds quartley at a rate of 6%... how much does this person have after 5 yrs...

do you have to this all over again... 6/4/100 +1... or do you just leave it as 6/100 + 1

 

[word.]

well you said yourself the quarterly rate was 6% so you just leave it at 6%
if it says 6% p.a. (per annum) then you divide by 4