sin62cos28+cos62sin28=sin(62+28)=1
(cos15°-sin15°)/(cos15°+sin15°)
分子分母同除以cos15
(1-tan15)/(1+tan15)
=(tan45-tan15)/(1+tan45tan15)
=tan(45-15)
=√3/3
sin62cos28+cos62sin28=sin(62+28)=1
(cos15°-sin15°)/(cos15°+sin15°)
分子分母同除以cos15
(1-tan15)/(1+tan15)
=(tan45-tan15)/(1+tan45tan15)
=tan(45-15)
=√3/3