急求sin30度除以sin10度减去cos30度除以cos10度,求值
问题描述:
急求sin30度除以sin10度减去cos30度除以cos10度,求值
答
sin30/sin10-cos30/cos10
=(sin30cos10-cos30sin10)/sin10cos10
=2sin(30-10)/(2sin10cos10)
=2sin20/sin20
=2