Maths help and explanations

Indiego

okiidokey
well im doing my j.c this year, and i have a pretty much flawless understanding of everything ive done so far, ive never not gotten below 99 in a maths test, so im ur gal

ive covered:
statistics
sets
algebra
coordinate geometry
pretty much everything else too
except geomety and like all that sin cos tan stuff

could anyone return the favour and explain wth sin cos and tan are all about?!?!?

also, should i be worrried that i still havent finished the maths course yet? i really dont like my teacher, he overcompensates for people in my (higher level ) class who should really be in o.l and i feel its slowing the class wayyy down

anywhoo sorry for the essay XD

Just Contribute

If you were finished your Maths course now, I would be worried. You won't have it finished by the Pres, and, apparently, you'll finish shorty before the Junior Cert.

As for Sin, Tan, and Cos - that's Trigonometry. Have you done that yet?

Indiego

no i havent done trignometry

Just Contribute

Indiego wrote: »

no i havent done trignometry

That's strange. Shouldn't you have done that in 2nd Year?

Basically, Sin, Cos, and Tan are ratios you use to help you find the length of an angle in a right-angled triangle. You'll understand it better when you cover it until then. There isn't really much point going into now to be honest.

TehFionnster

If you need a hand, I can help with Trig, I find all of it rediculously easy

Indiego

Just Contribute wrote: »

That's strange. Shouldn't you have done that in 2nd Year?

yeah i probably should have, but as i said, my teacher is just useless...
we have just over half the course finished...
and he also regularly suffers from dillusions where he is convinced we have covered something when we havent, and he doesnt listen when we tell him we havent, so i end up teaching myself, and then explaining it to my classmates afterwards, this is probably why i have such a good undertanding of what ive covered.
but i looked at the trig chapter and i was stumped...

Indiego

TehFionnster wrote: »

If you need a hand, I can help with Trig, I find all of it rediculously easy

o could you?!? it would be amazingggglyyy usefull and generous of you :O

TehFionnster

No prob, Just ask me what you want explained and I'll do my best :P

Indiego

TehFionnster wrote: »

No prob, Just ask me what you want explained and I'll do my best :P

welllll im not really sure where to start, i dont really even know what they are used for... 0_o
could you just explain the basics for me?

TehFionnster

Well, I'll explain the stuff in the pass book until you get it.
Then we'll get to the harder stuff.

Right, Trigonometry is dealing with triangles but for now, we'll only talk about right angle triangles.

Right angled triangles contain a 90 degree angle.
Hypotenuse is the longest side on a triangle.
It NEVER changes.
As my teacher says, "The longest side is opposite the largest angle"
which in this case will always be 90 degrees.
To find the area of these triangles you can use Pythagoras' Theorem
Which states, "The square on the hypotenuse is equal to the sum of the squares on the other two sides"

So basically, We'll call "c" the hypotenuse.
This is the formula

a^2 + b^2 = c^2

a,b or c can be substituted for "x" if you need to find a side
because this formula is so easy, it generally isn't asked simply.
I'll put up the sine, cossine and tangent later

Just Contribute

Meh! I think I need help with my revision. Mind helping out?

TehFionnster

Just Contribute wrote: »

Meh! I think I need help with my revision. Mind helping out?

Not at all, if that was directed at me :P

TehFionnster

Anything you want a hand with in particular?

Just Contribute

Cheers! There's nothing in particular so far. There's just a few things I got a bit confused on when I was rising.

The first thing is Solving Linear Equations. I can two the first two types, as in Texts and Tests 2, though I'm a tad confused on the final type.

For example, 1B Q54:

1/3 (x-1) = x -3/5 (x+2)

Do you just do both sides out into 15, the LCD, and then multiply out the brackets?

As in:

5 (x-1) = -9 (x+2)

TehFionnster

Right, I'd say multiply across by the figures on the bottom ie.

1/ 3(x-1) = x-3 /5(x+2
=1/3x-3 = x-3 /5x +10
= 1(5x+10) = (x-3)(3x-3)
5x+10 = 3x^2 - 3x -9x +9
3x^2 -5x -3x -9x -10 + 9 = 0
3x^2 -17x - 1 = 0

---

I think thats it :P

TimeToShine

Indiego wrote: »

okiidokey
well im doing my j.c this year, and i have a pretty much flawless understanding of everything ive done so far, ive never not gotten below 99 in a maths test, so im ur gal

ive covered:
statistics
sets
algebra
coordinate geometry
pretty much everything else too
except geomety and like all that sin cos tan stuff

could anyone return the favour and explain wth sin cos and tan are all about?!?!?

also, should i be worrried that i still havent finished the maths course yet? i really dont like my teacher, he overcompensates for people in my (higher
level ) class who should really be in o.l and i feel its slowing the class wayyy down


anywhoo sorry for the essay XD

That makes absolutely no sense at all. Anyone with half a maths brain could sit down, learn sohcahtoa and be done with trig. And give your maths teacher a break, its his job to get people to pass, so either get the book and start studying on your own or bear with it.

Just Contribute

TehFionnster wrote: »

Right, I'd say multiply across by the figures on the bottom ie.

1/ 3(x-1) = x-3 /5(x+2
=1/3x-3 = x-3 /5x +10
= 1(5x+10) = (x-3)(3x-3)
5x+10 = 3x^2 - 3x -9x +9
3x^2 -5x -3x -9x -10 + 9 = 0
3x^2 -17x - 1 = 0

---

I think thats it :P

The answer should be 13.

TehFionnster

Well, I fecked that one up :P

Slow Show

I finished my maths course before the mid-term...but I've a really good teacher and no other class in my year is anywhere near finishing. We're spending the rest of the year revising and doing papers, so I'm fairly confident about maths. But my class certainly doesn't represent the majority, and I'd say just go along with your teacher and don't worry - it'll all be done by June and trying to teach yourself maths is messy business, it only ends up confusing you - trust me.

Just Contribute

How could you have covered everything property?

Anyway, could you help me out?

Slow Show

Having an amazing teacher...and classes are streamed, so mine is made up of people who are expected to get A's, so there isn't too much distraction or messing.
And sure:

first of all i would expand the brackets

(x-1)/3=x-(3x+6)/5

find the lowest common multiple to get rid of the demoninator...in the case of 3 and 5 it's 15
so 15(x-1)/3=15x-15(3x+6)/5
5(x-1)=15x-3(3x+6)
5x-5=15x-9x-18
5x-5=6x-18
6x-5x=-5+18
x=13

I think that's right. :P

Indiego

TimeToShine wrote: »

That makes absolutely no sense at all. Anyone with half a maths brain could sit down, learn sohcahtoa and be done with trig. And give your maths teacher a break, its his job to get people to pass, so either get the book and start studying on your own or bear with it.

in what way does this make no sense at all?
it just happens that ive looked ahead at trig and its the only thing that hasnt clicked in my mind, amen't i aloud to not be perfect?
and yes, i know its my maths teachers job to get people to pass, but the o.l students should be in o.l and the h.l in h.l, he has even said to these people that they will be taking the o.l mock, so why are they still in the h.l class, all of them failed all the exams since 2nd year when we were divided.

whiteandlight

You would be surprised the number of students who will make it through higher level even having failed exams prior to that. Your teacher cannot force students to take ordinary level (and rightly so), their parents would be furious. He/She has to work to the level of the class. Its fantastic you are so far ahead, use the time wisely and help those around you. Teaching something and having to explain every detail will stick it solidly in your head.

With regard to the trigonometry, if you are working on your own then try this link
http://www.projectmaths.ie/documents/teachers/TL_8.pdf
This is for the new project maths course and it is a much better introduction for students than the old "learn this rhyme" method. If you run into any hassle PM me. However it is based on similar triangles in geometry, if you haven't done that go there in your book first (its the theorem involving ratios).
Good luck

Aldiily

Were nearly finished the Maths course!!!!We have 2 finish trigonometry and a bit of geometry two

Zaffy

Not sure if help is still needed, but.



Basically using your calculator, you input the numbers you have, so...

Example, Sin30 = 1/2

Which means Sin^-1(1/2 = 30

The theta (zero with a line through it) is just where you put the angle.
The numbers are the sides of the triangle.

Cos60 = 1/2 can be turned into 60 = Cos^-1(1/2

Hope that helps.

LiquidSquid

This may be slightly off topic but if you would like the revision sheets our teacher gave us for Geometry and for finding the incircle and circumcircle etc.

margarite

TimeToShine wrote: »

That makes absolutely no sense at all. Anyone with half a maths brain could sit down, learn sohcahtoa and be done with trig. And give your maths teacher a break, its his job to get people to pass, so either get the book and start studying on your own or bear with it.

Thanks everyone for your help, it really great that everyone took the time to help me, before I was banned which I deserved some kind person gave me an web address which helped me with all of the maths (Junior Cert.) which someone here in my home deleted by accident, if that person is reading and could give me that web address again I really would appreciate it. Once again thank you everybody for taking the time out of your own busy studying time to help me and I really very very grateful, and would like to wish you all good luck in what ever exams are facing you all. Again thank you very much and good luck.:)

margarite

Some very kind person send me an e mail address which helped out in all of the junion cert maths, if you are reading can you please send me that address again. Thank you.:)

suitcasepink

slow show wrote: »

Having an amazing teacher...and classes are streamed, so mine is made up of people who are expected to get A's, so there isn't too much distraction or messing.
And sure:

first of all i would expand the brackets

(x-1)/3=x-(3x+6)/5

find the lowest common multiple to get rid of the demoninator...in the case of 3 and 5 it's 15
so 15(x-1)/3=15x-15(3x+6)/5
5(x-1)=15x-3(3x+6)
5x-5=15x-9x-18
5x-5=6x-18
6x-5x=-5+18
x=13

I think that's right. :P

Yup that was very well done!
Fully correct

jumpguy

slow show wrote: »

Having an amazing teacher...and classes are streamed, so mine is made up of people who are expected to get A's, so there isn't too much distraction or messing.
And sure:

first of all i would expand the brackets

(x-1)/3=x-(3x+6)/5

find the lowest common multiple to get rid of the demoninator...in the case of 3 and 5 it's 15
so 15(x-1)/3=15x-15(3x+6)/5
5(x-1)=15x-3(3x+6)
5x-5=15x-9x-18
5x-5=6x-18
6x-5x=-5+18
x=13

I think that's right. :P

AWESOME STUFF EMMA, WOW!

Well done!

IloveConverse

Could someone please put up the solutions from text and tests two, page 153, questions 9, 10 and 11? I half got 9 and 11 and I'm stuck.. Thanks so much!