18. Diketahui untuk 0 < x < 360, hp dari persamaan tan 2x-1/4phi = tan1/4phi adalah

Jawab:

2x – π/4 = π/4

2x = 2π/4 + k.π

x = 1/4π + k. 1/2π

k = 0 , x = 1/4π

k = 1, x = 1/4 π + 1/2π = (1+2)/4π = 3/4π

k = 2, x = 1/4π + π = 5/4π

k = 3, x = 1/4π + 3/2π = (1+6)/4π = 7/4π

hp = { 1/4π, 3/4π, 5/4π, 7/4π}