(sin15°+cos15°）（sin15°-cos15°）的值为?
问题描述：
(sin15°+cos15°）（sin15°-cos15°）的值为?
答
原式=sin15^2-cos15^2=1-2*cos15^2=-cos30=-√3/2
(sin15°+cos15°）（sin15°-cos15°）的值为?
原式=sin15^2-cos15^2=1-2*cos15^2=-cos30=-√3/2