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| 1. |
Cos theta =sin105*+cos105* |
| Answer» RHS = sin(90+15) + cos(90+15) = sin90.cos15 + cos90.sin15 + cos90.cos15 - sin90.sin15 = cos15 + 0 + 0 - sin15 = cos(45-30) - sin(45-30) = cos45.cos30 + sin45.sin30 - sin45.cos30 + cos45.sin30 = √3/2√2 + 1/2√2 - √3/2√2 + 1/2√2 = 1/√2 = cos 45° therefore theta = 45 | |