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# C3 Trigonometry Help watch

https://qualifications.pearson.com/content/dam/pdf/A%20Level/Mathematics/2013/Exam%20materials/6665_01_pef_20120307.pdf

Edexcel Core Maths C3 January 2012 Q8c

I don’t understand how to get the second solution. According to the explanation, (pi-theta) > (theta-pi/6). But why?

If someone can explain this small step to me, I understand how to do the rest of my answer.
2. (Original post by HumzaAhmed)

https://qualifications.pearson.com/content/dam/pdf/A%20Level/Mathematics/2013/Exam%20materials/6665_01_pef_20120307.pdf

Edexcel Core Maths C3 January 2012 Q8c

I don’t understand how to get the second solution. According to the explanation, (pi-theta) > (theta-pi/6). But why?

If someone can explain this small step to me, I understand how to do the rest of my answer.
From what I can see you use what they tell you in part B. Divide through by (√3−x) and then that bit on the left is equal to tan(x+π/6). The just arctan both sides and solve for theta.
3. (Original post by wa17)
From what I can see you use what they tell you in part B. Divide through by (√3−x) and then that bit on the left is equal to tan(x+π/6). The just arctan both sides and solve for theta.
Arctan on both sides will get you the first solution. How does that lead to the second solution?
4. Note that tan is a periodic function where generally:

So in this case:

5. (Original post by simon0)
Note that tan is a periodic function where generally:

Yep I understand that. Its just that in order to use that, you need to know which angle is smaller and which angle is larger.
6. (Original post by HumzaAhmed)
Yep I understand that. Its just that in order to use that, you need to know which angle is smaller and which angle is larger.
No you don't.
7. (Original post by Prasiortle)
No you don't.
I get it now becuase the response was edited.

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