# C3 Basic Trig

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Thread starter 3 years ago
#1
tan2θcosec2θ
Simplify
I did tan2θ * 1/sin2θ = tan2θ/sin2θ
However, it is either wrong or i have not simplified far enough?
0
3 years ago
#2
is that tan2feta, or tan squared feta?
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Thread starter 3 years ago
#3
(Original post by DeGoldenGamer)
is that tan2feta, or tan squared feta?
tan 2 feta
0
3 years ago
#4
(Original post by DeGoldenGamer)
is that tan2feta, or tan squared feta?
Big man what's feta? Lmao, You making me hungry.
2
3 years ago
#5
(Original post by Desultory)
tan2θcosec2θ
Simplify
I did tan2θ * 1/sin2θ = tan2θ/sin2θ
However, it is either wrong or i have not simplified far enough?
You didn't really simplify it, you just changed the cosec to a sin

Given these are both functions of , you may be expected to use the double angle formulae to change these into expressions of just and

Give that a go and let us know what you come up with
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Thread starter 3 years ago
#6
(Original post by Ed5)
You didn't really simplify it, you just changed the cosec to a sin

Given these are both functions of , you may be expected to use the double angle formulae to change these into expressions of just and

Give that a go and let us know what you come up with
This is c3 year 13 maths? Sorry i dont know the double angle formulae
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3 years ago
#7
(Original post by Desultory)
This is c3 year 13 maths? Sorry i dont know the double angle formulae
If you're on edexcel, aye it's C3 and these formulae are a key part of it. They let you break down trignometric functions into more basic ones, e.g.

You should definitely cover it in class at some point so it's likely you just haven't reached the topic yet
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3 years ago
#8
(Original post by Desultory)
tan2θcosec2θ
Simplify
I did tan2θ * 1/sin2θ = tan2θ/sin2θ
However, it is either wrong or i have not simplified far enough?
Write and see what you notice.

You don't need to use double angle formulae for this question.
0
Thread starter 3 years ago
#9
(Original post by Ed5)
If you're on edexcel, aye it's C3 and these formulae are a key part of it. They let you break down trignometric functions into more basic ones, e.g.

You should definitely cover it in class at some point so it's likely you just haven't reached the topic yet
That is true but this is a section 6 question which is basic trig not section 7 which is further trig so i am not expexted to use that so i need another way?
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Thread starter 3 years ago
#10
(Original post by Notnek)
Write and see what you notice.

You don't need to use double angle formulae for this question.
i know tan theta = sin theta / cos theta but if its tan 2 theta, are you allowed to put a 2 infront of the sin and cos theta?
I didnt know that?
0
3 years ago
#11
(Original post by Desultory)
i know tan theta = sin theta / cos theta but if its tan 2 theta, are you allowed to put a 2 infront of the sin and cos theta?
I didnt know that?
Yes, the identity is and since it's an identity, it's true for all so you can replace with anything.

E.g.

or
0
3 years ago
#12
(Original post by Desultory)
That is true but this is a section 6 question which is basic trig not section 7 which is further trig so i am not expexted to use that so i need another way?
(Original post by Notnek)
Write and see what you notice.

You don't need to use double angle formulae for this question.
Must just be like this then. I wasn't really sure given you didn't mention the module, and 'simplify' can be quite open ended
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Thread starter 3 years ago
#13
(Original post by Notnek)
Yes, the identity is () and since it's an identity, it's true for all so you can replace with anything.

E.g.

or
Okay that makes sense thanks i worked it out now
However, if there is a question where its tan^2 theta, can that equal sin^2 theta / cos ^2 theta or not?
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Thread starter 3 years ago
#14
(Original post by Ed5)
Must just be like this then. I wasn't really sure given you didn't mention the module, and 'simplify' can be quite open ended
I appreciated the advice!
0
3 years ago
#15
(Original post by Desultory)
Okay that makes sense thanks i worked it out now
However, if there is a question where its tan^2 theta, can that equal sin^2 theta / cos ^2 theta or not?
Yes that's also true but for a different reason:

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Thread starter 3 years ago
#16
(Original post by Notnek)
Yes that's also true but for a different reason:

Okay thanks now these questions seem easy!
1
3 years ago
#17
(Original post by Desultory)
Okay thanks now these questions seem easy!
Getting good at C3/4 trigonometry is all about practice. Some students think they can get by if they just learn the identities but this doesn't work. You have to try as many different questions as you can to see how/where identities can be used and to pick up all the little tricks.

When a student tells me that they hate C3 trig (common), I know that they probably haven't practiced enough
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Thread starter 3 years ago
#18
(Original post by Notnek)
Getting good at C3/4 trigonometry is all about practice. Some students think they can get by if they just learn the identities but this doesn't work. You have to try as many different questions as you can to see how/where identities can be used and to pick up all the little tricks.

When a student tells me that they hate C3 trig (common), I know that they probably haven't practiced enough
haha i completely understand
are you a teacher of maths?
reccommend any good websites for tutors or even yourself?
0
3 years ago
#19
(Original post by Desultory)
haha i completely understand
are you a teacher of maths?
reccommend any good websites for tutors or even yourself?
Yes I teach/tutor. If you google "maths tutor" then you'll find websites where you can find tutors near you.
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Thread starter 3 years ago
#20
(Original post by Notnek)
Yes I teach/tutor. If you google "maths tutor" then you'll find websites where you can find tutors near you.
ok thanks

sec A - sec A * sin^2 A

i did 1/cos A - 1/cos A * 1-cos^2A) but it doesnt really simplify
have i done this wrong?
0
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