Trigonometric Functions:

If we place an angle in standard position or at origin and draw a circle with center at origin such that the circle will intersect terminal arm of the  angle , As shown in following figure:

Where “x” is the x-coordinate of the point  ”P”, “y” is the y-coordinate of point “P” and “r” the radius of circle.

Then for any angle of θ there are six trigonometric functions named: Sine , Cosine , Tangent , Cosecant , Secant and Cotangent

The above functions are defined by :

Sine of the angle θ = Sinθ=y/r

Cosine of the angle θ=Cosθ=x/r

Tangent of th angle θ=Tanθ=y/x

Cosecant of the angle θ=Cosecθ=r/y

Secant of angle θ=Secθ=r/x

Cotangent of angle θ=Cotθ=x/y

Note:

:-Cosecant , Secant and Cotangent are just inverse of Since , Cosine and Tangent respectively.

:-For some of the cases (when the denominator of the value of function if 0) or values of θ Cosecant , Secant , and Cotangent may not be defined.