Trigonometric Functions
The sine and cosine functions are defined as the vertical and horizontal projections of the coordinates of the terminal points respectively.
If x is the projection of the terminal point on the x-axis and y is the projection of the terminal point on the y-axis, then:
[tex]r^2=x^2+y^2[/tex]
Where r is the radius of the circle.
If we are given the value of the angle θ, then:
x = r cos θ
y = r sin θ
We are given the angle of the terminal point θ=5 radians and the x-coordinate of its terminal point as x=0.28
Solving the equation for r:
[tex]r=\frac{x}{\cos\theta}=\frac{0.28}{\cos 5}=0.9871[/tex]
Now we find the value of y
y = r sin 5
y = 0.9871 * (-0.9589) = -0.9465
The y-coordinate of the terminal point is y = -0.9465
