Diket x1+x2 merupakan persamaan [tex] \sqrt{2} [/tex] + 2cos x =0 interval 0≤x≤360 berapakah nilai x1+x2

√2 + 2 cos x = 0
2 cos x = -√2
cos x = -1/2 √2 ==> cos bernilai negatif di kuadran 2 dan 3
Kuadran 2 : x = (180° - 45°) = 135° = 3π/4
Kuadran 3 : x = (180° + 45°) = 225° = 5π/4
x1 + x2 = 135° + 225° = 360°
Atau
x1 + x2 = 3π/4 + 5π/4 = 8π/4 = 2π

Mapel : Matematika
Kelas : X SMA
Materi : Persamaan Trigono

Pembahasan :
√2 + 2Cos x = 0
2Cos x = -√2
Cos x = -1/2 √2
Cos x = Cos 135° , Cos 225°
x = 135° , 225°

Niali X1 + X2 = 135 + 225 = 360°