Question

Please help me find these values! sin 270, cos 180, and cot, tan, cosec.. how do i find the values for it? can anybody please explain me the unit circle theory! :'(

Answer 1

unit circle is a circle of radius 1 which gives the sine and cosine values for common angles such as multiples of 30, 45,60 all the way to 360 degrees.

The values come from ratios of special right triangles and definitions of the sine/cosine functions
sine = opposite/hypotenuse
cos = adjacent/hypotenuse


reference
http://en.wikipedia.org/wiki/File:Unit_circle_angles_color.svg

Answer 2

On the trig unit circle,
The axis OA represents the function f(x) = cos x
x - 0 (or 2Pi)--> cos x - 1; x = Pi/2 --> cos x = 0; x=Pi --> cos x = -1
The axis OB represents the function f(s) = sin x
x = 0 (or Pi or 2Pi) -> sin x = 0; x = Pi/2 -> sin x = 1; x = 3Pi/2 -> sin x = -1; x = Pi/4 -> tan x = 1; x = 3Pi /4 -> tan x = -1
The axis AT represents the function f(x) = tan x
x = 0, or 2Pi -> tan x = 0; x = Pi/2 or 3Pi/2 x = + or - infinity
The axis BU represent the function f(x) = cot x
x = 0, or Pi, or 2Pi, cot x = inf; x = Pi/2 -> cot x = 0