应该是你打错了吧?!
原式应该是cos(π/3+a)+sin(π/6+a)
=cosπ/3cosa-sinπ/3sina+sinπ/6cosa+cosπ/6sina
=cosa/2-(根号3)/2sina+cosa/2+(根号3)/2sina
=cosa
应该是你打错了吧?!
原式应该是cos(π/3+a)+sin(π/6+a)
=cosπ/3cosa-sinπ/3sina+sinπ/6cosa+cosπ/6sina
=cosa/2-(根号3)/2sina+cosa/2+(根号3)/2sina
=cosa