Aryabhata (476-550 CE) is widely regarded as the father of Indian trigonometry. He made significant contributions to the field, including the development of sine and cosine functions.

Aryabhata is credited with developing the concept of the sine function. He defined the sine of an angle as the ratio of the length of the opposite side to the length of the hypotenuse in a right triangle.

Bhaskara II (1114-1185 CE) developed the concept of the cosine function. He defined the cosine of an angle as the ratio of the length of the adjacent side to the length of the hypotenuse in a right triangle.

Brahmagupta (598-668 CE) developed the concept of the tangent function. He defined the tangent of an angle as the ratio of the length of the opposite side to the length of the adjacent side in a right triangle.

Varahamihira (505-587 CE) developed the concept of the secant function. He defined the secant of an angle as the ratio of the length of the hypotenuse to the length of the adjacent side in a right triangle.

Varahamihira also developed the concept of the cosecant function. He defined the cosecant of an angle as the ratio of the length of the hypotenuse to the length of the opposite side in a right triangle.

Brahmagupta also developed the concept of the cotangent function. He defined the cotangent of an angle as the ratio of the length of the adjacent side to the length of the opposite side in a right triangle.

Bhaskara II developed the concept of the inverse sine function. He defined the inverse sine of an angle as the angle whose sine is equal to the given value.

Bhaskara II also developed the concept of the inverse cosine function. He defined the inverse cosine of an angle as the angle whose cosine is equal to the given value.

Bhaskara II also developed the concept of the inverse tangent function. He defined the inverse tangent of an angle as the angle whose tangent is equal to the given value.

Bhaskara II also developed the concept of the inverse secant function. He defined the inverse secant of an angle as the angle whose secant is equal to the given value.

Bhaskara II also developed the concept of the inverse cosecant function. He defined the inverse cosecant of an angle as the angle whose cosecant is equal to the given value.

Bhaskara II also developed the concept of the inverse cotangent function. He defined the inverse cotangent of an angle as the angle whose cotangent is equal to the given value.

Indian mathematicians used trigonometry in astronomy to calculate the positions of stars and planets, predict eclipses, and determine the time of day.

Indian mathematicians used trigonometry in architecture to design temples and other buildings, determine the height of structures, and calculate the angles of roofs.