Question

cos5π/12cosπ/6+cosπ/12sinπ/6的值为

Answer 1

cos5π/12cosπ/6+cosπ/12sinπ/6
=sin(π/2-5π/12）cosπ/6+cosπ/12sinπ/6
=sinπ/12cosπ/6+cosπ/12sinπ/6
=sin(π/12+π/6)
=sinπ/4
=√2/2