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问题: 化简sin10°sin(-260°)-cos100°cos(-170°)-tan190°tan280

化简sin10°sin(-260°)-cos100°cos(-170°)-tan190°tan280°

解答:

sin10°sin(-260°)-cos100°cos(-170°)-tan190°tan280
=sin10sin100-(-sin10)cos190-tan10(-tan80)
=sin10cos10+sin10(-cos10)-tan10(-cot10)
=1