作业帮(cos55°+sin45°sin10°)/(sin55°-cos45°cos80°)＝?
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/05/11 19:28:08
(cos55°+sin45°sin10°)/(sin55°-cos45°cos80°)＝?
(cos55°+sin45°sin10°)/(sin55°-cos45°cos80°)＝?
cos55°+sin45°sin10°
=cos(10°+45°)+sin45sin10
=cos10cos45-sin45sin10+sin45sin10
=cos10cos45
sin55-cos45cos80
=sin(10+45)-cos45cos80
=sin10cos45+sin45cos10-cos45cos80
=sin45cos10
sin45=cos45
∴原式=1
cos55°+sin45°sin10°
=cos(10°+45°)+sin45sin10
=cos10cos45-sin45sin10+sin45sin10
=cos10cos45
sin55-cos45cos80
=sin(10+45)-cos45cos80
=sin10cos45+sin45cos10-cos45cos80
=sin45cos10
sin45=cos45
∴原式=1
(sin10°+sin50°)/sin35°sin55°的值
不查表求cos80°cos35°+cos10°cos55°的值．
cos30°cos45°+sin30°sin45°等于多少?
cos30°* sin45 °+ cos60°* cos45°
化简 cos15°cos45°-cos75°sin45°
(sin30°-cos45°)(cos30°+sin45°)/(cos45°的平方+tan30°*sin60°)-3ta
sin60°×cos60°+sin45°×cos45°-sin30°×cos30°等于多少
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计算cos45°-cos60°分之sin30°-2sin45°+根号3tan30°
cos60°+tan60° 2/根号2sin45°+sin60°-2cos45°
根号【cos45°-cos30°】*2-tan60°分之tan45°+sin45°
sin45°/(cos60°-tan60°)+cos45°×cos30°=