Name: joeseph
Who is asking: Student
Level: Secondary

Question:
Can you please tell me some history of the trigonometric ratio Tangent? who discovered it? when was it discovered and some other useful info...

Hi Joeseph,
The place that I look for answers to this type of question is Earliest Known Uses of Some of the Words of Mathematics. This is a resource maintained by Jeff Miller, a teacher at Gulf High School in New Port Richey, Florida. In it he has

TANGENT (as a trigonometric ratio) was introduced by Thomas Fincke (1561-1656) in his Thomae Finkii Flenspurgensis Geometriae rotundi libri XIIII, Basileae: Per Sebastianum Henricpetri, 1583. He wrote tangens in Latin. In English, TANGENT is found in 1594 in Exercises by Thomas Blundevil.

There is also an answer to a similar question on Trigonometry here at Math Central.

Cheers,
Penny