Trigonometric Question (further maths/uni level) HELP!!!!

h_y

Hi

I've attached them in a file :smile:

(edited 9 years ago)

Original post by h_y

Hi

I'm struggling with how to explain this but will do my best! I'm doing a self-taught? course to get into university through open awards. I'm not sure if many of you are familiar with it but I basically don' have any teachers or tutors so when I get stuck I turn to revision guides and mainly online help.

I've got a May exam coming up on trigonometric methods and in all the practice questions I've gathered there are 2 that I am completely stuck on and can not do. So I would appreciate any help anyone can give me at all.

I've been trying to set up the questions with the LaTeX method but I keep messing it up! They are long(ish) so if anyone wants to have a go at them could you please just post below and i'll PM them you straight away! They are higher then A-level math questions (as in the difficulty wise) so i'll say around university level? I'm not 100 percent on that though.

Thank you for reading and thanks for any help! -H

no need for LaTeX
Post a photo is the quickest way

Reply 2

h_y

OP

Original post by TeeEm

no need for LaTeX
Post a photo is the quickest way

thanks I'll do it now...................

done :smile:

i think it's right

(edited 9 years ago)

Reply 3

User1443542

11

I'll try and have a crack at some of them. I'm doing Edexcel FM, so maybe

Reply 4

h_y

OP

Original post by devangdave

I'll try and have a crack at some of them. I'm doing Edexcel FM, so maybe

Thank you

I've attached a doc file with the questions :smile:

Reply 5

TeeEm

19

Original post by h_y

thanks I'll do it now...................

done :smile:

i think it's right

the first two are very standard A level questions and most people here would be able to help you.

the last one is challenging but look at Q352 in this link
(very long time to download)

http://madasmaths.com/archive/maths_booklets/standard_topics/trigonometry/trigonometry_exam_questions.pdf

I did the solution to practically the same question.

Reply 6

h_y

OP

Original post by TeeEm

the first two are very standard A level questions and most people here would be able to help you.

the last one is challenging but look at Q352 in this link
(very long time to download)

http://madasmaths.com/archive/maths_booklets/standard_topics/trigonometry/trigonometry_exam_questions.pdf

I did the solution to practically the same question.

Thanks for having a look at it :smile:

Do you mean question 18? cause I haven't come across a question like that so i have nothing to refer back to and don't know where to start. Thanks for that i'm going to check it out now :smile:

Reply 7

TeeEm

19

Original post by h_y

Thanks for having a look at it :smile:

Do you mean question 18? cause I haven't come across a question like that so i have nothing to refer back to and don't know where to start. Thanks for that i'm going to check it out now :smile:

I very busy at present
for Q18 look at similar questions on
http://madasmaths.com/archive/maths_booklets/standard_topics/trigonometry/trigonometry_r_transformations.pdf

Reply 8

h_y

OP

Original post by TeeEm

I very busy at present
for Q18 look at similar questions on
http://madasmaths.com/archive/maths_booklets/standard_topics/trigonometry/trigonometry_r_transformations.pdf

No worries :smile:

Thanks for them links they look really helpful. I'm going to spend time now and go through and have another go at it :smile:

Hopefully will get somewhere with it

Reply 9

h_y

OP

Original post by TeeEm

the first two are very standard A level questions and most people here would be able to help you.

the last one is challenging but look at Q352 in this link
(very long time to download)

http://madasmaths.com/archive/maths_booklets/standard_topics/trigonometry/trigonometry_exam_questions.pdf

I did the solution to practically the same question.

Hi You know that link you posted and you said have a look at question 352? I still don't know what i'm doing there. Thanks :smile:

Reply 10

TeeEm

19

Original post by h_y

Hi You know that link you posted and you said have a look at question 352? I still don't know what i'm doing there. Thanks :smile:

Well the question has a full solution and it assumes you know all the standard trig identities.

what course are you on and what is your mathematical background?

Reply 11

h_y

OP

Original post by TeeEm

Well the question has a full solution and it assumes you know all the standard trig identities.

what course are you on and what is your mathematical background?

...........

(edited 9 years ago)

Reply 12

TeeEm

19

Original post by h_y

I'm doing a access to medical health professions course. Which include a maths, physics and biology module. My maths is poor in Russia I've done the equivalent to half a maths A-level so an 'as' in maths I think it's called. But that's about it.

That may explain why you find this so hard.

I would love to help but I am tied up with my own work at present and it seems that the room is dead (Friday night + Football).

Hopefully later or tomorrow some of the regulars here might be able to help but my advice is to discuss these with your course tutor or borough/buy an A level textbook which covers trigonometry at A2 level and self study.

I hope it all goes well.

Reply 13

h_y

OP

Original post by TeeEm

That may explain why you find this so hard.

I would love to help but I am tied up with my own work at present and it seems that the room is dead (Friday night + Football).

Hopefully later or tomorrow some of the regulars here might be able to help but my advice is to discuss these with your course tutor or borough/buy an A level textbook which covers trigonometry at A2 level and self study.

I hope it all goes well.

no worries, thank you for your help though :smile:

Reply 14

ghostwalker

17

Original post by h_y

...

Q19.

From

\sin2P+\sin 2Q + \sin 2R

Obvious first step is the double angle formula.

Then, we want to use P+Q+R=pi. We have a choice of changing the sine or the cosine. One leads us to the desired result, and the other to another result.

In this case changing the sine works:

Now

\sin x = \sin (\pi-x)

for all x.

So,

\sin P = \sin (\pi-[Q+R])= \sin(Q+R)

Applying that three times and expanding the

\sin(Q+R)

etc., we end up with:

=4(\sin P \cos Q \cos R + \cos P\sin Q\cos R+ \cos P \cos Q \sin R)

We now want to start combining the P,Q,R, so we can exploit the P+Q+R=pi.

Looking at the first two terms we get:

=4(\sin (P+Q) \cos R + \cos P \cos Q \sin R)

Now we want to construct sin (P+Q+R), so we need cos(P+Q)sin(R) out of that second term. Clearly it's not there as is, so we need to add (and subtract so nothing changes) a term, which is sinPsinQsinR.

Can you finish - save me doing all the LaTex.

Trigonometric Question (further maths/uni level) HELP!!!!

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