已知sin(π/6+α)=1/4,则cosα+根号三sinα的值为A.-1/4B.1/2C.2D.-1

Question

已知sin(π/6+α)=1/4,则cosα+根号三sinα的值为
A.-1/4 B.1/2 C.2 D.-1

Answer 1

cosα+根号三sinα
=2*(1/2*cosα+根号三/2*sinα)
=2*(sin(π/6)*cosα+cos(π/6)*sinα)
=2*sin(π/6+α)
=2*(1/4)
=1/2