Sin, Cos, Tan – SOH CAH TOA
In right triangle ABC
sin = Side opposite to angle theta / Hypotenuse
cos = Side adjacent to angle theta / Hypotenuse
tan = Side opposite to angle theta / Side adjacent to angle theta
For cot, sec & cosec
cosec = 1/ sin
sec = 1/cos
cot = 1/tan
Example
Find value of sin, cos, tan, cosec, cot, sec
Given a triangle with sides 3, 4, 5
Here, Opposite side = 4
Adjacent Side = 3
Hypotenuse = 5
So, our values are
sin = Side opposite to angle theta / Hypotenuse = 4/5
cos = Side adjacent to angle theta / Hypotenuse = 3/5
tan = Side opposite to angle theta / Side adjacent to angle theta = 4/3
For cot, sec & cosec
cosec = 1/ sin = 5/4
sec = 1/cos = 5/3
cot = 1/tan = 3/4
To learn the formulas,
we use SOH CAH TOA
SOH = sin equals opposite by Hypotenuse
sin = Opposite/Hypotenuse
CAH = cos equal adjacent by hypotenuse
cos = Adjacent/Hypotenuse
TOA = tan equals opposite by adjacent
tan = Opposite/Adjacent

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.