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(1)化简:根号2sin(π/4-x)+根号6cos(π/4-x)

来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/04/20 01:57:43
(1)化简:根号2sin(π/4-x)+根号6cos(π/4-x)
(2)sin(67°-x)cos(x-22°)+cos(67°-x)cos(112°-x)的值为
(1)化简:根号2sin(π/4-x)+根号6cos(π/4-x)
=2(根号2)[(1/2)sin(π/4-x)+(根号3)/2 *cos(π/4-x)]
=2(根号2)[sin(π/4-x)cos(π/3)+cos(π/4-x)sin(π/3)]
=2(根号2)sin[(π/4-x)+π/3]
=2(根号2)sin(7π/12 -x)
(2)sin(67°-x)cos(x-22°)+cos(67°-x)cos(112°-x)
=sin(67°-x)cos(x-22°)+cos(67°-x)cos[90°-(x-22°)]
=sin(67°-x)cos(x-22°) + cos(67°-x)sin(x-22°)
=sin[67°-x)+(x-22°)]
=sin45°
=(根号2)/2