Jawabanmu

2014-04-06T21:27:08+07:00
Jika tan 1/2 = y/x
maka sin x= dicari dulu R (phytgoras) = akar 5
maka sin x = y/r = 1/akar 5

2014-04-06T21:42:05+07:00
Tan1/2x = t
sin1/2x = t  / akar(t^2 +1)
cos1/2x = 1/ akar(t^2 +1 )

sinx = sin2. 1/2x = 2. sin1/2x. cos 1/2x = 2. [t  / akar(t^2 +1)] .[1/ akar(t^2 +1 )] = 2t /(t^2 +1)
3 4 3