Trigonometry 2 – Solutions
Warm Up Question A:
1. cos(θ°) =
=>Reference angle = 30
Cos is positive in the 1st and 4th quadrants
1st quadrant = 30
4th quadrant = 360 - 30 = 330
2. sin(θ°) =
=> reference angle 45°
Sin is positive in the 1st and 2nd quadrants
1st quadrant: 45°
2nd quadrant: 180° – 45° = 135°
3. Tan(θ°) = -1
=> reference angle 45°
Tan is negative in the 2nd and 4th quadrants
2nd quadrant: 180° - 45° = 135°
4th quadrant: 360° - 45° = 315°
Warm Up Question B:
Answer:
2sinxcosx + sinx = 0
(sin2x = 2sinxcosx p14 of tables)
sinx(2cosx + 1) = 0
sinx = 0
or
2cosx + 1 = 0
sinx = 0
cosx = -1/2
Reference angle = 0
Reference angle = 60
x = 0 ,180 ,360
Cos is negative in the 2nd and 3rd
quadrants
x= 0 , 120 180 , 240 or 360
2nd quadrant:
180 - 60 = 120
3nd quadrant:
180 + 60 = 240
Question 1 Solutions
Question 2 Solutions
(iii)
Use 49 as 49 < 90
27 is the angle at Y
All angles must sum to 180 so the remaining angle must equal 104
Question 3
(a)
(b)
(b) alternative solution:
Question 4 Solutions