(sin15°－cos15°)/(sin15°+cos15°)=

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(sin15°－cos15°)/(sin15°+cos15°)=

(sin15°－cos15°)/(sin15°+cos15°)=
(sin15°－cos15°)/(sin15°+cos15°)=

(sin15°－cos15°)/(sin15°+cos15°)=
(sin15°－cos15°)/(sin15°+cos15°)【分子分母同乘上sin15°+cos15°】
=【（sin15)^2-(cos15)^2】/【1+2sin15cos15】
=-cos30/[1+sin30]
=-(根号3/2)/(1+1/2)
=-根号3 /3

原式=sin²15-cos²15
=-(cos²15-sin²15)
=-cos(2×15)
=-cos30
=-√3/2

(sin15°－cos15°)/(sin15°+cos15°)= 化简sin15°-cos15°/sin15°+cos15° sin15°-cos15°/sin15°+cos15°的值? 化简sin15°-cos15°/sin15°+cos15° sin15°-cos15°/sin15°+cos15°的值? sin15°cos15°等于 sin15°+cos15°过程 sin15°cos15°等于? 化简：sin15°*cos15° cos15°-sin15°=? sin15°cos15°= sin15°cos15°是什么意思 sin15°+cos15°= 求cos15°-tan15°/cos15°+sin15° 化简（sin15 °+cos15°）2 sin15°=?cos15°=? 求sin15°+cos15°的值 sin15°cos15°怎么算