Jawabanmu

2014-02-27T21:07:41+07:00
|a||b|cos A = (2)(1) + (-1)(-2) + (1)(1)
(√6)(√6)cos A = 5
cos A = 5/6
sin A =  \sqrt{1-cos^2A}
sin A =  \sqrt{1- \frac{25}{36} }
sin A =  \sqrt{ \frac{11}{36} }
sin A = \frac{1}{6}  \sqrt{11}

CMIIW :3