Trigonometric functions are mathematical functions of an angle. There are six basic trigonometric functions (sine (sin), cosine (cos), tangent (tan), cotangent (cot), secant (sec), cosecant (cosec)), commonly defined as ratios of two sides of a right triangle. Used in diagnostic imaging for Cartesian sampling, to describe radio frequency signals, etc.

A tumor is a growth of abnormal cells that are either malignant or benign.