sin165°cos75°+cos15°sin105°等于?

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sin165°cos75°+cos15°sin105°等于?
sin165°cos75°+cos15°sin105°等于?

sin165°cos75°+cos15°sin105°等于?
原式=sin(180-15)cos75+cos75sin(180-75)
-sin15cos75+cos75sin75
=sin(15+75)
=sin90
=1

sin165°cos75°+cos15°sin105°
=sin15°sin15°+cos15°cos15°
=1

原式=sin(180-15)cos75+cos75sin(180-75)
-sin15cos75+cos75sin75
=sin(15+75)
=sin90
=1

sin165cos75+cos15sin105
=sin(90+75)cos75+cos(60-45)sin(60+45)
=cos75cos75+(cos60cos45+sin60sin45)(sin60cos45+cos60sin45)
=cos(45+30)cos75+(√2/4+√6/4)(√6/4+√2/4)
=(cos45cos30-sin45sin30)cos75+3/8+1/8+√3/4
=(√6/4-√2/4)^2+1/2+√3/4
=3/8-√3/4+1/8+1/2+√3/4
=1

sin165°cos75°+cos15°sin105°等于? cos75°cos15°-sin255°sin165°的值是?写下过程就行/// cos75°cos15°-sin255°sin165°的值是 cos15°cos75°=? 计算tan15°+cos15°/cos75° cos75°-cos15°的值等于? cos15°+cos75°怎么做 cos75°,cos15°分别得多少? (cos75°)^2+(cos15°)^2+cos75°cos15°= (tan75°-tan15°)cos75°cos15° sin15°cos75°+cos15°sin105°=? (cos15°-cos75°)(sin75°+sin15°)＝? 1sin15°cos75°+cos15°sin105°=? sin15°cos75°+cos15°sin75° cos15°cos30°cos60°cos75°= cos15°cos45°－cos75°sin45° cos75°-cos15°=请详细解答 √3/2cos15°-(1/2)cos75°=