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# Maths C3 - Trigonometry... Help?? Watch

1. (Original post by Philip-flop)
Expanded as in like?....
Attachment 583512

Where do I go from here though?
From there I would probably multiply top and bottom by 1+tan(60)tan(45).

Then use tan(45) = 1 and tan(60) = root(3) and then simplify.
2. Can anyone help me with this?...

3. (Original post by Philip-flop)
Can anyone help me with this?...

and
4. (Original post by NotNotBatman)
and
I'm assuming you meant

Thanks a lot for your help

How did you realise to do that from that equation? I never would have spotted it if it wasn't for your help
5. Ffs, now I'm stuck on part (g).

Am I even doing it right for this question?...
Attachment 583808583810

EDIT: Don't worry, I managed to work this out in a very strange way
Attached Images

6. Guys do you know how to solve these questions. They are from C1

1. Find vaalues of the constants A,B and C in identity
4x2 - 18x +29 = A(x-4)2 - B (x-2) + C

2. The equation x2 + 3px + p = 0, where p is a non-zero constant and has equal roots. Find the value of p.
7. (Original post by AB J)
Guys do you know how to solve these questions. They are from C1

1. Find vaalues of the constants A,B and C in identity
4x2 - 18x +29 = A(x-4)2 - B (x-2) + C

2. The equation x2 + 3px + p = 0, where p is a non-zero constant and has equal roots. Find the value of p.
Expansion may help you can see what A is going to be anyway, because there's only one x^2 term on the RHS.

For 2, if you are given that a quadratic has equal roots.. what calculation can you perform?
8. (Original post by AB J)
Guys do you know how to solve these questions. They are from C1

1. Find vaalues of the constants A,B and C in identity
4x2 - 18x +29 = A(x-4)2 - B (x-2) + C

2. The equation x2 + 3px + p = 0, where p is a non-zero constant and has equal roots. Find the value of p.
9. (Original post by Philip-flop)
Ffs, now I'm stuck on part (g).

Am I even doing it right for this question?...
Attachment 583808583810

EDIT: Don't worry, I managed to work this out in a very strange way
Note that , then rewrite the second sin term as an appropriate cos.
10. I'm probably being stupid. But how do I even work out part (a) of this question? I'm assuming it's to do with the difference of two squares?...
11. (Original post by Philip-flop)
I'm probably being stupid. But how do I even work out part (a) of this question? I'm assuming it's to do with the difference of two squares?...
I would change the sin^2(theta) into 1 - cos^2(theta) and then work from there
12. (Original post by asinghj)
I would change the sin^2(theta) into 1 - cos^2(theta) and then work from there
oh right so I would do?...

.... But then where do I go from here?
13. (Original post by Philip-flop)
oh right so I would do?...

.... But then where do I go from here?
what is the double angle formula:
?
14. (Original post by asinghj)
what is the double angle formula:
?
I'm not sure I know. The Edexcel C3 Modular Maths textbook hasn't even explained double angle formulas. But from what I've just found out...

... and so on from there (what I showed in my last comment).
15. (Original post by Philip-flop)
I'm not sure I know. The Edexcel C3 Modular Maths textbook hasn't even explained double angle formulas. But from what I've just found out...

... and so on from there (what I showed in my last comment).
oh ok.. so yes

this can be simplified to

because
and this made me realise you didn't have to change the into anything...

oh and watch this video
http://www.examsolutions.net/tutoria...=C3&topic=1420
16. (Original post by asinghj)
oh ok.. so yes

this can be simplified to

because
and this made me realise you didn't have to change the into anything...

oh and watch this video
http://www.examsolutions.net/tutoria...=C3&topic=1420
Oh right, I see. So for this question my answer would literally be...

17. (Original post by Philip-flop)
I'm probably being stupid. But how do I even work out part (a) of this question? I'm assuming it's to do with the difference of two squares?...
For part a), later on in the textbook you'll learn about the double angle formula and the expression will be a form you recognise.

At this stage of the textbook, you should be looking to write the expression as the right-hand-side as one of the addition formulae.

So .

Can you see what to do from here?
18. (Original post by notnek)
For part a), later on in the textbook you'll learn about the double angle formula and the expression will be a form you recognise.

At this stage of the textbook, you should be looking to write the expression as the right-hand-side as one of the addition formulae.

So .

Can you see what to do from here?
I don't think I know where to go from there.

All I know is...

19. (Original post by Philip-flop)
I don't think I know where to go from there.

All I know is...

You don't need to do anything else. is a single trig function so you're done.
20. (Original post by notnek)
You don't need to do anything else. is a single trig function so you're done.
Oh I see. Thank you so much notnek !!

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