Question

sin12分之π等于?根号2cos12分之π？等于？？

Answer 1

∵cos2x=1-2(sinx)^2

∴sinx=√[(1-cos2x)/2]

∴sin(π/12)=sin[(π/6)/2]=√[1-cos(π/6))/2]=√[(2-√3)/4]=√(2-√3)/2