Question

tan（π/12）+cos（π/12）=

Answer 1

tan2a的公式我忘了!这样也可以：

tan(π/12)=sin(π/12)/cos(π/12);

sin(π/12)=sin(π/6)/2cos(π/12);

cos(π/12)=根号下(1+2cos方π/6)/2