Angle (argument of a function): \(\alpha\)

Trigonometric functions: \(\sin \alpha, \) \(\cos \alpha ,\) \(\tan \alpha, \) \(\cot \alpha,\) \(\sec \alpha,\) \(\csc \alpha \)

Trigonometric functions: \(\sin \alpha, \) \(\cos \alpha ,\) \(\tan \alpha, \) \(\cot \alpha,\) \(\sec \alpha,\) \(\csc \alpha \)

Coordinates of a point on a circle: \(x\), \(y\)

- Four quadrants of the unit circle

The trigonometric circle is divided into \(4\) quarters (quadrants). The first quadrant corresponds to the angle interval \(0^\circ \lt \alpha \lt 90^\circ,\) the second quadrant lies in the interval \(90^\circ \lt \alpha \lt 180^\circ,\) the third quadrant corresponds to the interval \(180^\circ \lt \alpha \lt 270^\circ,\) and the fourth quadrant covers the angles \(270^\circ \lt \alpha \lt 360^\circ.\) - The signs of the trigonometric functions depend on the quadrant in which the angle lies. The table below shows the signs of \(6\) trigonometric functions in quadrants \(I-IV\).
- Signs of the trigonometric functions in the unit circle