Question

求式子2sin80°sin50°+sin10°cos10°(1+tan10°)的值.

Answer 1

思路分析:将tan10°化为tan10°=是求值过程中最关键的一步.

解:原式=2sin80°sin50°+

=2sin80°sin50°+2sin10°(cos10°+sin10°)

=2sin80°sin50°+2sin10°cos50°

=2(cos10°sin50°+sin10°cos50°)

=2sin60°=2×=.