Comments on: Trigonometry Type R

By: Hermes Chong

Hermes Chong — Mon, 30 Jan 2012 08:51:52 +0000

@Im__Rachelx3 http://t.co/I9bQLPwL not so accurate but what is needed is there unless is not this R formula you talking about.

By: Kwek Seowmeng

Kwek Seowmeng — Sun, 30 Oct 2011 06:59:58 +0000

@ValerieLim_ @Limshinru http://t.co/yrijAs4S

By: MA

MA — Mon, 10 Oct 2011 07:36:25 +0000

@colour_pencils http://t.co/dMwILudw hahah idk how to explain cuz i dun have my phone xD

By: Miss Loi

Miss Loi — Wed, 28 Sep 2011 05:56:58 +0000

Hello and welcome to Jφss Sticks, Ray! From parts 2(i) & 2(iii) of the workings here, OM = √40 cos (θ+18.43°) AM = √40 sin (θ+18.43°) This means that both the lengths of OM and AM are dependent on the same angle θ, which, looking at the equations above, means that both cannot be maximum at the same value of θ i.e. When OM is maximized when cos (θ + α) = 1, AM is actually minimized at this same value of θ since sin (θ + α) = 0. So the key here is we need an intermediate value of θ that will maximize the area instead of the individual lengths hence we have to obtain the ONE R-formula for the area using the double-angle formula etc.

By: Ray

Ray — Tue, 27 Sep 2011 06:38:01 +0000

Hi Miss Loi,

I love your site and your sense of humour, definitely very localised.

Anyway, a quick question to your type-R question 2, the part on maximum area of the triangle.

Should we apply the maximum value of R at the length stage? meaning to AM and OM individually instead of applying to the area straghit?

The maximum value of AM and OM exist when cos (θ + α) =1, Hence, maximum value for AM and OM should be √40. Hence, 1/2 times AM times OM should give us 20cm sq.?

I'm confused. Pls clarify if you can? Thanks! =]

By: weijie

weijie — Wed, 10 Nov 2010 08:37:25 +0000

why cannot r be negative 5 in the exaple given ?

By: Miss Loi

Miss Loi — Mon, 01 Nov 2010 15:24:23 +0000

If Miss Loi gets your question right ... the Factor Formulae refer to

Are they called the same thing over at Reggae Jamaica?

By: Miss Loi

Miss Loi — Mon, 01 Nov 2010 15:15:14 +0000

Are you referring to this diagram? If so, you'll find in ΔOAB from the diagram above that θ < 90° − α

By: Jukie Primestein

Jukie Primestein — Fri, 29 Oct 2010 22:33:17 +0000

which trig identity do you refer to as the factor formula?

By: Jukie Primestein

Jukie Primestein — Fri, 29 Oct 2010 20:51:59 +0000

Can you please send me a few more variation of the roar R-formula. Based on a few times I encountered it it is not always clear if you are to find a maximum or minimum! Oh another question I have not seen any proof to convince me than cosine of a negative number is positive, but please don't get me wrong I know it is correct however a proof maybe through a diagram would really do the trick!