Question

I need to solve question 3

Answer 1

3) 3.sec² Ф = 4.tan² Ф
 but sec² Ф = 1/cos² Ф
3/cos² Ф = 4.tan² Ф
3/4 = (tan² Ф).(cos² Ф) ; tan² Ф = sin² Ф/cos² Ф

3/4 = (sin² Ф)x(cos² Ф)/(cos² Ф)

sin² Ф = 3/4 

a) sin Ф = +(√3)/2       and  b) sin Ф = - (√3)/2

 sin Ф = + - (√3)/2 → Ф =π/3 + kπ/3