Trignometry Formulae (2 Viewers)

[mojako]

Originally posted by wildtiger
thanks mercury =P

Sum or Differences to Products <=== would that come in handy if we learn it? coz my teacher just told us its not in the syllabus and skipped it.

Just memorise one of the four forms and you can write sin(90degree - x) as cos(x), etc. And yes you can use the formulae in 3U and even 2U exam.

 

[Grey Council]

wtf?!

lol, people COULD make this sheet themselves, I'm surprised so many people are so grateful.

lol, don't take this wrong, I'm just commenting. It's very nice of you, mercury, to go to the bother.

 

[abdo]

i certainly can not make a sheet like that... that'll take hours if not days.

i've memorized the sheet... all thanks mercury... now im kicking ass in trig

 

[Vampire]

one word...legend

 

[paper cup]

man, I could have saved myself an hour or so if I had only visited this thread this morning

Thank you heaps, may you find further happiness in doing more things to benefit poor little BOSers like me in the near and foreseeable future..

 

[mr EaZy]

top stuff mate! how do u memorise the products of sum and differences? i memorised them a long time ago but forgot them!

 

[mr EaZy]

i remember now, i used to derive them on the spot, they are simply the solutions to the sum of angles ie: sin (a+b) +sin (a-b), something like that.....
im glad u put in t=tan@ values, i lost 3 marks in the trials for that!!

 

[Slidey]

Uh, shouldn't people at a 3 unit level know these off by heart?

 

[CrashOveride]

Uh, shouldn't people at a 3 unit level know these off by heart?

Yes, yes they should.

 

[Captain pi]

Those not in the syllabus

Those Trigonometric formulæ not in the syllabus, although important to recognize, cannot be simply quoted a priori/without proof in any exam. Such failure to prove those identities may result in zero marks being awarded for that question.

 

[Slidey]

Those Trigonometric formulæ not in the syllabus, although important to recognize, cannot be simply quoted a priori/without proof in any exam. Such failure to prove those identities may result in zero marks being awarded for that question.

You used both an æsc and a piece of Latin. I commend you.

 

[Kutay]

you have forgotten one Double Angle

Tan2x = 2tanx / 1 - tan^2x

btw thats a good formula sheet but need to put that in

 

[richz]

thank you this is handy

 

[Slidey]

you have forgotten one Double Angle

Tan2x = 2tanx / 1 - tan^2x

btw thats a good formula sheet but need to put that in

It is not necessary to add this, as it can be easily derived in two ways:
tan(x+x)=tan2x=(tanx+tanx)/(1-tanx.tanx)
tan2x=2tanx/(1-tan^2(x)) #

Or:
Given tanx=2t/(1-t^2)
Substitute in t=tan(x/2):
tanx=tan(2*x/2)=2tan(x/2)/(1-tan^2(x/2))
x/2 is a generic angle. It can be replaced by x to give:
tan2x=2tanx/(1-tan^2(x)) #

 

[Trev]

Yes, but who can be bothered deriving formulae in an exam situation? And better yet, who has the time?

 

[Slidey]

It would take all of 2 seconds to derive what I mentioned above.

 

[acmilan]

Yes, but who can be bothered deriving formulae in an exam situation? And better yet, who has the time?

Pressure arises in tests...you question whether a simple formula that you have remember was remembered correctly. Deriving it will confirm your worries

 

[Mumma]

I hate trig

 

[karen88]

thnx so much... so needed it to memorise for my 3u exam 2mr

 

[auzbabe4christ]

awesome

thanx heaps 4 this mercury!
itll help a heap!
ur awesome dude!