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| 1. |
Find sin 75 using sin(a+b)=sina*cosb+cosa*sinb |
| Answer» Let a be 45 and b be 30sin 75 = sin ( 45 + 30) = sin 45 * cos 30 + cos 45 * sin 30= cos (90 - 45) * cos 30 + cos 45 * cos (90- 30)= cos 45 * cos 30 + cos 45 * cos 60= cos 45 ( cos 30 + cos 60 )= cos 45 ( cos 90)=cos 45 (0)= 0 | |