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:
![r^2=x^2+y^2](https://img.qammunity.org/2023/formulas/mathematics/college/wdjhwi4huh0mns5abr5vfni9ohfwt1o3nq.png)
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:
![r=(x)/(\cos\theta)=(0.28)/(\cos 5)=0.9871](https://img.qammunity.org/2023/formulas/mathematics/college/8n9b72nlf8mt3obw0jhtpatpeklayk9tjp.png)
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