Jawabanmu

2014-05-23T10:46:41+07:00
Sin x = cos x  ruas kiri dan kanan dibagi cos x
sinx/cosx = cosx/cosx
tan x = 1
      x = 45' , 225' , 405'
         = π/4 . 5π/4 , 9π/4
HP { π/4 , 5π/4 , 9π/4 }