Consider the triangle, having the angles and sides as shown in the figure.

**1)** **Law of Sine is**

**2) Laws of Cosine are**

or

or

or

**3) Laws of Tangent are**

__HALF ANGLE FORMULAS__

Consider that and are sides and angles of , as shown above, also if **(i) **

**(ii)**

**4) **

**5) **

**6) **

**7) **

**8) **

**9) **

**10) **

**11) **

**12) **