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Question : 22 of 160
Marks:
+1,
-0
Solution:
‌| 1 |
| sin‌((k+1)‌+‌)⋅sin‌(‌+‌) |
Multiplying
Nr and
Dr by
sin‌π∕6,
‌‌‌‌| sin‌{((k+1)+)−(+)} |
| 2((k+1)‌+‌)⋅sin‌(‌+‌) |
‌=2[cot(‌+‌)−cot((k+1)‌+‌)}‌‌‌+{cot(‌+‌)−cot(‌+‌)}‌‌‌+...+{cot(‌+‌)−cot(‌+‌)}‌=2[cot‌+cot(‌+‌)]‌=2[1−‌]=2(‌)=‌‌=2(√3−1)
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