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November 08, 2025, 02:06:16 pm
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Author Topic: TRIGALICOUS  (Read 1094 times)  Share 

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Inside Out

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TRIGALICOUS
« on: April 16, 2011, 07:36:31 pm »
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 :D  For (pie/2)<x<pie with cosa=-sinb where o<b<(pie/2), find a in terms of b





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BubbleWrapMan

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Re: TRIGALICOUS
« Reply #1 on: April 16, 2011, 07:52:55 pm »
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*noms trig*

These questions love diagrams. Try it, then report back.
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Tim Koussas -- Co-author of ExamPro Mathematical Methods and Specialist Mathematics Study Guides, editor for the Further Mathematics Study Guide.

Current PhD student at La Trobe University.

Water

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Re: TRIGALICOUS
« Reply #2 on: April 16, 2011, 07:54:25 pm »
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(pie/2)<x<pie with cosa=-sinb where o<b<(pie/2)


cos a = -sin b



sin (pi/2 + a ) = sin (b + pi)

pi / 2 + a = b + pi

           a = b + pi/2

           a =  (b + pi/2)



Not sure if this is right, can I get it confirmed :)?

*Corrected*


        
« Last Edit: April 16, 2011, 08:20:30 pm by Water »
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About Philosophy

When I see a youth thus engaged,葉he study appears to me to be in character, and becoming a man of liberal education, and him who neglects philosophy I regard as an inferior man, who will never aspire to anything great or noble. But if I see him continuing the study in later life, and not leaving off, I should like to beat him - Callicle

Inside Out

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Re: TRIGALICOUS
« Reply #3 on: April 16, 2011, 07:56:08 pm »
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answer is : b + pi/2
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Water

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Re: TRIGALICOUS
« Reply #4 on: April 16, 2011, 08:01:34 pm »
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cos a =   - sin b

        =    cos ( pi/2 + b)


           a = pi/2 + b


I'll check with other, dunno why it doesn't work ):
   


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About Philosophy

When I see a youth thus engaged,葉he study appears to me to be in character, and becoming a man of liberal education, and him who neglects philosophy I regard as an inferior man, who will never aspire to anything great or noble. But if I see him continuing the study in later life, and not leaving off, I should like to beat him - Callicle

Inside Out

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Re: TRIGALICOUS
« Reply #5 on: April 16, 2011, 08:04:07 pm »
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ok thanks :)
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Inside Out

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Re: TRIGALICOUS
« Reply #6 on: April 16, 2011, 08:14:15 pm »
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how do you know whether cosa=sin (pi/2 - a ) or sin (pi/2 + a )
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Water

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Re: TRIGALICOUS
« Reply #7 on: April 16, 2011, 08:22:52 pm »
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Complementary angles, two ways to learn it, either graph it out and understand theory, or rote learn it. :), Yeah sorry, fixed my error before xD
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About Philosophy

When I see a youth thus engaged,葉he study appears to me to be in character, and becoming a man of liberal education, and him who neglects philosophy I regard as an inferior man, who will never aspire to anything great or noble. But if I see him continuing the study in later life, and not leaving off, I should like to beat him - Callicle

Inside Out

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Re: TRIGALICOUS
« Reply #8 on: April 16, 2011, 08:25:20 pm »
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yes but can't cosa= either sin (pi/2 + a )  or sin (pi/2 -a ).. how did u know which one to chose?
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enpassant

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Re: TRIGALICOUS
« Reply #9 on: April 16, 2011, 08:33:28 pm »
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For (pie/2)<x<pie
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Inside Out

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Re: TRIGALICOUS
« Reply #10 on: April 16, 2011, 08:57:27 pm »
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yep i get that now :)...
but how come -sinb cant equal sin(2pi-b) instead of sin(pi+b)
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enpassant

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Re: TRIGALICOUS
« Reply #11 on: April 16, 2011, 11:19:51 pm »
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Quote from: happyface on April 16, 2011, 08:57:27 pm
yep i get that now :)...
but how come -sinb cant equal sin(2pi-b) instead of sin(pi+b)
-sinb cant equal sin(2pi-b) because this will give a=3pi/2 - b which is not in the second quad as required ((pie/2)<x<pie)
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Water

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Re: TRIGALICOUS
« Reply #12 on: April 16, 2011, 11:20:56 pm »
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 o<b<(pie/2)



 sin (b + pi)


Wouldn't this therefore be wrong, as this will be not be in the 1st quad? My method of figuring this out could be completely wrong , I'm doubting  ):!
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About Philosophy

When I see a youth thus engaged,葉he study appears to me to be in character, and becoming a man of liberal education, and him who neglects philosophy I regard as an inferior man, who will never aspire to anything great or noble. But if I see him continuing the study in later life, and not leaving off, I should like to beat him - Callicle

enpassant

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Re: TRIGALICOUS
« Reply #13 on: April 16, 2011, 11:38:20 pm »
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Quote from: Water on April 16, 2011, 11:20:56 pm
o<b<(pie/2)



 sin (b + pi)


Wouldn't this therefore be wrong, as this will be not be in the 1st quad? My method of figuring this out could be completely wrong , I'm doubting  ):!

symmetry property: -sinb=sin(b+pi)=sin(2pi-b)
b in the first quad, b+pi in the third quad and 2pi-b in the fourth quad
-sinb cant equal sin(2pi-b) because this will give a=3pi/2 - b which is not in the second quad as required  by (pi/2)<a<pi
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Water

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Re: TRIGALICOUS
« Reply #14 on: April 16, 2011, 11:41:08 pm »
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Quote from: enpassant on April 16, 2011, 11:38:20 pm
Quote from: Water on April 16, 2011, 11:20:56 pm
o<b<(pie/2)



 sin (b + pi)


Wouldn't this therefore be wrong, as this will be not be in the 1st quad? My method of figuring this out could be completely wrong , I'm doubting  ):!

symmetry property: -sinb=sin(b+pi)=sin(2pi-b)
b in the first quad, b+pi in the third quad and 2pi-b in the fourth quad
-sinb cant equal sin(2pi-b) because this will give a=3pi/2 - b which is not in the second quad as required  by (pi/2)<a<pi


excellent explanation :) You are awesome xD
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About Philosophy

When I see a youth thus engaged,葉he study appears to me to be in character, and becoming a man of liberal education, and him who neglects philosophy I regard as an inferior man, who will never aspire to anything great or noble. But if I see him continuing the study in later life, and not leaving off, I should like to beat him - Callicle
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