InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
\sin ^ { 2 } 15 ^ { \circ } + \sin ^ { 2 } 645 ^ { \circ } : |
|
Answer» Sin²15° + sin²645° we know, sin(n × 360° - Ф) = -sinФ , use this here [ n is integers ]Sin645° = sin(2 × 360 - 75°) = - sin75° And we know, sin(90 - Ф) = cosФ So, - sin75° = -sin(90-15°) = -cos15° Hence, sin645° = -cos15° Now, sin²15° + {-cos15°}² = Sin²15 + cos²15° = 1 [ ∵ sin²x + cos²x = 1 ] Hence, answer should be 1 |
|