Penjelasan dengan langkah-langkah:

no.5

sinx = cosx ; 0 ≤ x ≤ 2π

kedua ruas di bagi dgn cosx

sinx/cosx = cosx/cosx

tanx = 1

x = 45° (dikuadran 1)

x = π/4

x = 180° + 45 (dikuadran 2)

x = 225

x = 5π/4

HP = { π/4 dan 5π/4)

jawabannya : C

no. 6

4sin²x = 1 ; 0 ≤ x ≤ π/2

2(2sin²x) = 1

2(1 - cos2x) = 1

2 - 2cos2x = 1

2cos2x = 1

cos2x = 1/2

cos2x = cos60° (kuadran 1)

2x = 60° + k.360

x = 30° + k.180°

k = 0

x = 30° = π/6

k = 1

x = 210° = 7π/6 (tidak memenuhi interval)

cos2x = cos(-60°) ....(catatan : cosx = cos(-x))

2x = -60 ° + k.360°

x = - 30° + k.180°

k = 0

x = -30° = -π/6 (tidak memenuhi interval)

k = 1

x = -30 + 180°

x = 150° = 5π/6

nilai x yg memenuhi {π/6 dan 5π/6}

jawabannya : D