问题
填空题
sin80°cos35°-sin10°cos55°=______.
答案
sin80°cos35°-sin10°cos55°
=sin(90°-10°)cos35°-sin10°cos(90°-35°)
=cos10°cos35°-sin10°sin35°
=cos(10°+35°)
=cos45°
=
.2 2
故答案为:2 2
sin80°cos35°-sin10°cos55°=______.
sin80°cos35°-sin10°cos55°
=sin(90°-10°)cos35°-sin10°cos(90°-35°)
=cos10°cos35°-sin10°sin35°
=cos(10°+35°)
=cos45°
=
.2 2
故答案为:2 2