Q11 of 44 Page 79

Find the value of x in the following:

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

We know that,


sin(A - B) = sinAcosB - cosAsinB


LetA = 60°, B = 30°


Then,


sin 60° cos 30° – cos 60°sin 30°


= sin(60° - 30° )


= sin30°


∴sin 2x = sin 60° cos 30° – cos 60°sin 30°


⇒ sin 2x = sin30°


⇒ 2x = 30°



⇒ x = 15°


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