Jawabanmu

2013-12-10T00:23:59+07:00
Sin a = 1/3 maka cos a =  \frac{ \sqrt{8}}{3}

tan b = 1/5 maka sin b =  \frac{1}{ \sqrt{26}}  dan cos b =  \frac{5}{ \sqrt{26}}

sin2(a+b)=2.sin(a+b).cos(a+b)
=2.{sin a.cos b +cos a.sin b}{cos a.cos b - sin a.sin b}
tinggal disubstitusikan masing-masing nilainya
2 3 2