sinπ/24-cosπ/24等于多少

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sinπ/24-cosπ/24等于多少sinπ/24-cosπ/24等于多少sinπ/24-cosπ/24等于多少sinπ/24-cosπ/24=sin15°-cos15°=-【cos15°-sin1

sinπ/24-cosπ/24等于多少
sinπ/24-cosπ/24等于多少

sinπ/24-cosπ/24等于多少
sinπ/24-cosπ/24
=sin15°-cos15°
=-【cos15°-sin15°】
= -【cos(45°- 30°) - sin(45°- 30°)】
=-【 cos45°cos30°+ sin45°sin30°- sin45°cos30°+ cos45°sin30°】
=-【 √2/2 * cos30°+ √2/2 * sin30°- √2/2 * cos30°+ √2/2 * sin30°】
=-【 √2/2 * ( cos30°+ sin30°- cos30°+ sin30°)】
=- √2/2 * ( 2 * sin30°)
= -√2/2 * ( 2 * 1/2)
= √2/2