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Question : 41 of 120
Marks:
+1,
-0
Solution:
To find the value of
tan‌36°+tan‌9°+tan‌36°.tan‌9°, consider
A=36° and
B=9° We know that,
tan(A+B)=| tan‌A+tan‌B |
| 1−tan‌A.tan‌B |
⇒tan(36°+9°)=| tan‌36°+tan‌9° |
| 1−tan‌36°.tan‌9° |
⇒tan(45°)=| tan‌36°+tan‌9° |
| 1−tan‌36°.tan‌9° |
⇒1=| tan‌36°+tan‌9° |
| 1−tan‌36°.tan‌9° |
⇒1−tan‌36°.tan‌9°=tan‌36°+tan‌9° ⇒tan‌36°+tan‌9°+tan‌36°.tan‌9°=1
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