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Question : 26 of 160
Marks:
+1,
-0
Solution:
Given that
ABC is a triangle
So,
A+B+C=180∘Given,
C=60∘⇒‌‌A+B=120∘.......(i)We have by sine formula
‌‌=‌⇒‌‌‌=‌=2+√3‌ (given) ‌ Applying componendo and dividendo, we get
‌‌| sin‌A+sin‌B |
| sin‌A−sin‌B |
=‌=‌⇒‌| 2sin‌()⋅cos() |
| 2‌cos(‌)‌s‌i‌n‌(‌) |
=‌‌| (3+√3)(√3−1) |
| (√3+1)(√3−1) |
⇒‌‌cot(‌)=√3⇒√3‌cot(‌)=√3⇒(‌)=45∘ ⇒‌‌A−B=90........(ii)Solving Eqs. (i) and (ii), we get
∠A=105∘
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