sin(2a+π/3)+sin(2a-π/3)化简急用呢

问题描述:

sin(2a+π/3)+sin(2a-π/3)化简
急用呢

sin(2 a + π / 3)+ sin(2 a - π / 3)
= sin 2 a cos π / 3 + cos 2 a sin π / 3 + sin 2 a cos π / 3 - cos 2 a sin π / 3
= 2 sin 2a cos π / 3
= 2 × (1 / 2)sin 2a
= sin 2 a
参考公式:
sin(A+B) = sinAcosB+cosAsinB

sin(A-B) = sinAcosB-cosAsinB
参考资料:http://zhidao.baidu.com/question/88193418.html