check these out! mysterious formulas!! (3 Viewers)

[supermike]

hey i found these formulas (those 3 circled in red) from phoenix hsc math ext1 course summary. they dont seem to appear in any other books but they look quite handy, given that u ve to use reverse chain rule otherwise. i just wanna know if these are BOS approved, in other words, CAN I USE THEM IN HSC???

THANKS

 

[lychnobity]

LOL they're basic trigonometric integration formulas in extension 2.

Of course you can use them, just trig variants of the reverse chain rule. (I'm quite sure extension 2 methods are allowed in extension 1)

 

[Drongoski]

As far as I'm concerned I don't see why not? But bureaucrats may rule differently.

 

[supermike]

ths 4 assuring, these will be my life savers for the upcoming half yearly exam!!!

 

[Uncle]

I hope you do know those formulas enclosed in the red box are simply just applications of the chain rule associated with trigonometric functions.

 

[gurmies]

Lol @ "mysterious"

 

[hopethisworks]

doh

 

[supermike]

I hope you do know those formulas enclosed in the red box are simply just applications of the chain rule associated with trigonometric functions.

so do we ve to derive them by first applying chain rule or can we use them straight away to our heart's content???

has anyone actually used them in exams or assessment tasks be4?? r they BOS approved???

 

[hopethisworks]

you can use anything you like you fucking koordon

 

[Absolutezero]

As long as the working is logical, you can whatever formulas you want. No matter how hard they are, or where they came from.

 

[Timothy.Siu]

well, they're nto really formulas but yeah u can just use them

e.g.

Ssin^n xcosx dx
u probably could just go to
=sin^n+1 x/(n+1)

but i guess if u wanna be safe, just go
Ssin^n xcosx dx=Ssin^n x d(sinx)=sin^n+1 x/(n+1)
i'm sure they cant take marks off for that

 

[EvoRevolution]

Lol

 

[madsam]

Whenever i get a question like that, i write
|sin^n xcosx
= |f(x)^n . f(x)
= f(x)^n+1 / n+1

= sin^n+1 / n+1 + C


the teacher only every ticks it and says good work

 

[Schoey93]

I am only in Year 10, so I will understand if you guys don't take me seriously; however I am doing the top grade in Year 10. I am not completely stupid is all.


I agree with the people who said you can use whatever formulae you like, given that your working is logical. When we (the 50 people doing yr 10 advanced at my school) had our Trig test in Wk 10 last term, some people used Heron's formula to find the area of triangles instead of using the formula A=1/2sinab (correct me if that's wrong)... and they still got full marks!

so, um, yeah... it seems to not matter what formula you use just so long as it has a legitimate proof and so on.

 

[oly1991]

I am only in Year 10, so I will understand if you guys don't take me seriously; however I am doing the top grade in Year 10. I am not completely stupid is all.


I agree with the people who said you can use whatever formulae you like, given that your working is logical. When we (the 50 people doing yr 10 advanced at my school) had our Trig test in Wk 10 last term, some people used Heron's formula to find the area of triangles instead of using the formula A=1/2sinab (correct me if that's wrong)... and they still got full marks!

so, um, yeah... it seems to not matter what formula you use just so long as it has a legitimate proof and so on.

yeh in most cases it doesn't matter what method you use but some markers might look for specific methods when working out questions. And i don't know why people used heron's formula when it is so much more complicated.

P.S: the formula is 1/2absinC lol

 

[Dragonmaster262]

I think those formulas are present in the Terry Lee 3 unit book as well.

 

[cutemouse]

lol, they're just applications of the reverse chain rule...

I think those formulas are present in the Terry Lee 3 unit book as well.

Yeah his 3U book also has Integration by parts questions in it lol

 

[Schoey93]

yeh in most cases it doesn't matter what method you use but some markers might look for specific methods when working out questions. And i don't know why people used heron's formula when it is so much more complicated.

P.S: the formula is 1/2absinC lol

now I remember! lol

Thank you!!

 

[Schoey93]

lol, they're just applications of the reverse chain rule...


Yeah his 3U book also has Integration by parts questions in it lol

If it's too complicated, don't tell me, but... what's 'integration'?

Is that where you substitute algebraic symbols into an equation instead of putting values for those symbols in? (Is it the opposite to 'substitution'?)


Laugh at me if you want... we haven't learnt that yet though...

 

[cutemouse]

Integration is the process of finding the area underneath a graph.