In a right-angled triangle, we consider an angle 'x'
Sin(x) = $$\dfrac{opposite}{hypotenuse}$$
Cos(x) = $$\dfrac{adjacent}{hypotenuse}$$
Tan(x) = $$\dfrac{opposite}{adjacent}$$
Trigonometric values for important angles: 0, 30, 45, 60, 90.
Sin(0) = 0, Sin(30) = 1/2, Sin(45) = 1/$$\sqrt{\ 2}$$, sin(60) = $$\frac{\sqrt{\ 3}}{2}$$, sin(90) = 1
Cos(0) = 1, Cos(30) = $$\frac{\sqrt{\ 3}}{2}$$, cos(45) = 1/$$\sqrt{\ 2}$$, cos(60) = 1/2, cos(90) = 0
Tan(0) = 0, Tan(30) = $$\frac{1}{\sqrt{\ 3}}$$, Tan(45) = 1, Tan(60) = $$\sqrt{\ 3}$$, Tan(90) = infinity.
Sin(90+x) = cos(x)
Cos(90+x) = -sin(x)
sin(-x) = -sin(x)
cos(-x) = cos(x)
$$\sin^2\left(x\right)+\cos^2\left(x\right)=1$$
sin(x+y) = sin(x)cos(y) + cos(x)sin(y)
cos(x+y) = cos(x)cos(y) - sin(x)sin(y)
