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C3 trig question help (exact values)

trig.png
https://imgur.com/a/dcmhwE9 Hi, so I came across this in a C3 revision sheet from Physics and Maths tutor and I had completely forgot this even existed. I do Edexcel maths spec and I haven't been able to find any past paper questions on this (except one from June 2006). Does anyone have any/know of any questions on this topic which I could use to practice? Also, this question only uses sin and cos? Could a question be asked using, tan, sec, cosec, cot as well like this? Regards.
(edited 5 years ago)
Ironically on the same website you can find questions by topic for all exam boards for all types of Maths subjects

http://www.physicsandmathstutor.com/a-level-maths-papers/c3-by-topic/

Maybe start off with these http://pmt.physicsandmathstutor.com/download/Maths/A-level/C3/Topic-Qs/Edexcel-Set-1/C3%20Trigonometry%20-%20Trigonometric%20equations.pdf and then move on to these http://pmt.physicsandmathstutor.com/download/Maths/A-level/C3/Topic-Qs/Edexcel-Set-1/C3%20Trigonometry%20-%20Trigonometric%20formulae.pdf?

You see after a time they have really repetitive format, and you use only a few very key formula to then basically be able to solve any one you come across, its all about practice and being able to see instinctively/by knowledge what to do in your next step

Example of key formula
sin^2 + cos^2 = 1 (you can derive squared cosec, squared sec and squared cot from this)
sin/cos = tan
sin (a+b) = sin a cos b + sin b cos a
cos (a+b) = cos a cos b - sin a sin b

It's worth noting that the formula booklet has the equations for (a + b) for all three trigonometric identities
(edited 5 years ago)
Original post by Rollersteaam
Ironically on the same website you can find questions by topic for all exam boards for all types of Maths subjects

http://www.physicsandmathstutor.com/a-level-maths-papers/c3-by-topic/

Maybe start off with these http://pmt.physicsandmathstutor.com/download/Maths/A-level/C3/Topic-Qs/Edexcel-Set-1/C3%20Trigonometry%20-%20Trigonometric%20equations.pdf and then move on to these http://pmt.physicsandmathstutor.com/download/Maths/A-level/C3/Topic-Qs/Edexcel-Set-1/C3%20Trigonometry%20-%20Trigonometric%20formulae.pdf?

You see after a time they have really repetitive format, and you use only a few very key formula to then basically be able to solve any one you come across, its all about practice and being able to see instinctively/by knowledge what to do in your next step
Hi, thank you for your help but I was refering to specifically questions on acute and obtuse angles like in the picture I have provided. I have done every past paper since 2005 and I have only come across one question from June 2006 (attatched) which are regarding this. Capture.PNG(and some other, similar, but not as specific as this one). Fear not, I have not forgotten the whole trigonometry chapter when the exam is on Tuesday!
Reply 3
Original post by usuallymathshelp
trig.png
https://imgur.com/a/dcmhwE9 Hi, so I came across this in a C3 revision sheet from Physics and Maths tutor and I had completely forgot this even existed. I do Edexcel maths spec and I haven't been able to find any past paper questions on this (except one from June 2006). Does anyone have any/know of any questions on this topic which I could use to practice? Also, this question only uses sin and cos? Could a question be asked using, tan, sec, cosec, cot as well like this? Regards.

Yes they could involve any trig ratio. The best place to find questions like this is in the main Edexcel textbook. Do you have a copy? You won't find many in past papers as you've noticed.
Original post by usuallymathshelp
Hi, thank you for your help but I was refering to specifically questions on acute and obtuse angles like in the picture I have provided. I have done every past paper since 2005 and I have only come across one question from June 2006 (attatched) which are regarding this. Capture.PNG(and some other, similar, but not as specific as this one). Fear not, I have not forgotten the whole trigonometry chapter when the exam is on Tuesday!


Haha, apologies I didn't fully read the question, been revising all day for C3 so I'm a little loopy right now, assumed you were a year 12 trying to get a head start on C3 haha. I wish you luck for the exam.
Original post by Notnek
Yes they could involve any trig ratio. The best place to find questions like this is in the main Edexcel textbook. Do you have a copy? You won't find many in past papers as you've noticed.


Hi,
Yes I have a textbook to practice these questions. I just sometimes don’t find the text books as helpful because they don’t always explain how they got their answer and I always use the Model Answers to understand where I went wrong. Is there a reason there are no PPQs on this topic. Is it unlikely to come up?
Reply 6
Original post by usuallymathshelp
Hi,
Yes I have a textbook to practice these questions. I just sometimes don’t find the text books as helpful because they don’t always explain how they got their answer and I always use the Model Answers to understand where I went wrong. Is there a reason there are no PPQs on this topic. Is it unlikely to come up?

I can't think of any reason why. It's definitely not a popular question type to appear in Edexcel but there's no reason why it wouldn't appear this year.

If you need help with any question on this topic let me know.
Reply 7
WTAF? Is this Edexcel?! Did I miss this in the book? :s-smilie::frown:
Reply 8
Original post by kd_11
WTAF? Is this Edexcel?! Did I miss this in the book? :s-smilie::frown:

You see a lot of these types of questions in the main Edexcel textbook.
old spec btw
(was changed after 2008 i think)
Reply 10
Original post by Jefferyhenderson
old spec btw
(was changed after 2008 i think)

This type of question was never directly mentioned in any spec, new or old. Clearly it's not a popular question if you look at past papers but there's no reason why it wouldn't appear in this year's exam, just like any other question type related to this topic.
Original post by usuallymathshelp
Hi, thank you for your help but I was refering to specifically questions on acute and obtuse angles like in the picture I have provided. I have done every past paper since 2005 and I have only come across one question from June 2006 (attatched) which are regarding this. Capture.PNG(and some other, similar, but not as specific as this one). Fear not, I have not forgotten the whole trigonometry chapter when the exam is on Tuesday!


Question, I did that question in the picture but where did the negative sign come from?
Original post by Jefferyhenderson
Question, I did that question in the picture but where did the negative sign come from?


Because if you draw the cast diagram, between 270 and 360, cos angles only are positive. Therefore when you work out sinA it is negative because in that segment sin is negative. Then when you do 2sinacosa your overall figure is negative.
Original post by usuallymathshelp
Because if you draw the cast diagram, between 270 and 360, cos angles only are positive. Therefore when you work out sinA it is negative because in that segment sin is negative. Then when you do 2sinacosa your overall figure is negative.


ah ye
thanks man
Original post by Jefferyhenderson
ah ye
thanks man


i’m a girl but you’re welcome 🤗
Loool u guys still haven’t done ur c3 exam? I do AQA and finished C3 C4 last week. Good luck to u lot!
Original post by usuallymathshelp
i’m a girl but you’re welcome 🤗


ok thanks girl

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