Question

On a separate piece of paper sketch a unit circle with angle 0 in standard position. For what values of θ is the sine increasing? Decreasing? For what values of θ is the cosine increasing? Decreasing? For which angle between 0° and 360° is sine equal to 0? Where is cosine equal to 0? Please help(:

Answer 1

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°