1) Sine is the y-component in the unit circle. It grows from 0 t o1 in the sector 0° to 90 °, then starts to decrease from 1 to -1 until 270° where it starts to increase again from 270° to 360° (0°=.
2) Cosine is the x - component in the unit circle. It decreases from 1 to - 1 in the sector 0° to 180°, and increases from -1 to +1 in the sector 180° to 360°.
3) Sine is equal to 0 at angles 0° and 180°.
4) Cosine is equal to 0 at angles 90° and 270°
