Angles in all four Quadrants

• In the A quadrant (top right), sin, cos and tan are all positive
• In the S quadrant (top left), only sin is positive
• In the T quadrant, (bottom left), only tan is positive
• In the C quadrant (bottom right), only cos is positive

\(\(x^2+y^2=1\)\)

On a unit circle,
- the sin() of an angle is the x co-ordinate of the point
- the cos() of an angle is the y co-ordinate of the point
- the tan() of an angle is the gradient of the line drawn to the point from the origin