Question

If cos2x = cos60° cos30° + sin60° sin30° , find sin 2x

Answer 1

Answer:

± 1 / 2

Step-by-step explanation:

Recall the formula:

cos ( A - B ) = cos A cos B + sin A sin B

cos 2x = cos 60° cos 30° + sin 60° sin 30°

=> cos 2x = cos (60° - 30°)

=> cos 2x = cos 30°

=> sin 2x = ± sin 30°

=> sin 2x = ± 1 / 2