Jawabanmu

2014-05-16T17:59:42+07:00
F(x) = 2Sinx + Cosx
f'(x) = 2Cosx - Sinx
f'(π/2) = 2Cosπ/2 - Sinπ/2
           = 2(0) - 1
           = 0 - 1
           = - 1