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प्रश्न
Prove that : cos60° . cos30° - sin60° . sin30° = 0
उत्तर
L.H.S. = cos60° . cos30° - sin60° . sin30°
= `(1)/(2) xx sqrt(3)/(2) - sqrt(3)/(2) xx (1)/(2)`
= `sqrt(3)/(4) - sqrt(3)/(4)`
= 0
= R.H.S.
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