Answer:
The value of Ф is 3π/2
Step-by-step explanation:
* Lets revise the angle Ф in the four quadrant
∵ r = √(x² + y²) ⇒ square the two sides
∴ x² + y² = r²
∵ r = 1
∴ x² + y² = 1
∵ cos² Ф + sin² Ф = 1
∵ x is the adjacent side to Ф and y is the opposite side to Ф
∴ x = cos Ф and y = sin Ф
- At point (1 , 0)
∵ x = 1 , y = 0
∴ cos Ф = 1 and sin Ф = 0
∵ The positive part of x-axis represents the angle 0 and 2π
∴ cos 0 and 2π are 1 and sin 0 and 2π are 0
- At point (0 , 1)
∵ x = 0 , y = 1
∴ cos Ф = 0 and sin Ф = 1
∵ The positive part of y-axis represent the angle π/2
∴ cos π/2 is 0 and sin π/2 is 1
- At point (-1 , 0)
∵ x = -1 , y = 0
∴ cos Ф = -1 and sin Ф = 0
∵ The negative part of x-axis represents the angle π
∴ cos π is -1 and sin π is 0
- At point (0 , -1)
∵ x = 0 , y = -1
∴ cos Ф = 0 and sin Ф = -1
∵ The negative part of y-axis represent the angle 3π/2
∴ cos 3π/2 is 0 and sin 3π/2 is 1
* For the value of Ф = 3π/2 is sin Ф = -1
