If sin ( A-B ) = sinA cosB - cosA sinB and cos ( A-B ) = cosA cosB + sinA sin B. Find the value of sin 15 degrees and cos 15 degrees.
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sin15° =sin(60°-45°)
=sin60°cos45°-cos60°× sin45
=√3/2×1√2-1/2×1/√2
=√3/2√2-1/2√2
=√3-1)/2√2
Cos15°=cos (60°-45°)
=COS 60°cos45°+sin60°sin45°
=1/2×1/√2. +√3/2×1/√2
=1/2√2+√3/2√2
=√3+1/2√2
=sin60°cos45°-cos60°× sin45
=√3/2×1√2-1/2×1/√2
=√3/2√2-1/2√2
=√3-1)/2√2
Cos15°=cos (60°-45°)
=COS 60°cos45°+sin60°sin45°
=1/2×1/√2. +√3/2×1/√2
=1/2√2+√3/2√2
=√3+1/2√2
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