sin(x-y)=sinxcosy-sinycosx
2sin15°+cos45°=2sin(60°-45°)+cos45°=
=2sin60°cos45°-2sin45°cos60°+cos45°=
=2×(√3/2)×(√2/2) - 2×(√2/2)×1/2 + (√2/2)=
=2×(√6/4) -(√2/2) + (√2/2)=2(√6/4)=√6/2
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sin(x-y)=sinxcosy-sinycosx
2sin15°+cos45°=2sin(60°-45°)+cos45°=
=2sin60°cos45°-2sin45°cos60°+cos45°=
=2×(√3/2)×(√2/2) - 2×(√2/2)×1/2 + (√2/2)=
=2×(√6/4) -(√2/2) + (√2/2)=2(√6/4)=√6/2