Aryabhata is widely regarded as the father of Indian trigonometry due to his significant contributions to the field in the 5th century CE.

Aryabhata developed the sine table, which played a crucial role in the development of trigonometry.

The sine function is defined as the ratio of the length of the opposite side to the length of the hypotenuse in a right triangle.

The cosine function is defined as the ratio of the length of the adjacent side to the length of the hypotenuse in a right triangle.

The tangent function is defined as the ratio of the length of the opposite side to the length of the adjacent side in a right triangle.

The cotangent function is defined as the reciprocal of the tangent function.

Aryabhata developed the concept of the sine of an angle, which is a fundamental concept in trigonometry.

Bhaskara II developed the concept of the cosine of an angle, which is another fundamental concept in trigonometry.

Brahmagupta developed the concept of the tangent of an angle, which is a fundamental concept in trigonometry.

Varahamihira developed the concept of the cotangent of an angle, which is a fundamental concept in trigonometry.

Aryabhata developed the concept of the secant of an angle, which is a fundamental concept in trigonometry.

Bhaskara II developed the concept of the cosecant of an angle, which is a fundamental concept in trigonometry.

Brahmagupta developed the concept of the versine of an angle, which is a fundamental concept in trigonometry.

Varahamihira developed the concept of the haversine of an angle, which is a fundamental concept in trigonometry.

Aryabhata developed the concept of the exsecant of an angle, which is a fundamental concept in trigonometry.