jika diketahui f(x) = sin 1/2 x + cos 1/2 x maka nilai f(1/2 phi) adalah

x = 1/2 π = 1/2. 180 = 90°

f(1/2π) = sin 1/2 (90°) + cos 1/2 (90°)
= sin 45° + cos 45°
= 1/2 √2 + 1/2 √2
= √2