Function triAArA

triAArA(a1, a2, checkLevel?): [number, string]
Calculate the third angle of a triangle from the first two angles
Parameters
- a1: number
  the first angle of the triangle in radian
- a2: number
  the second angle of the triangle in radian
- checkLevel: ECheck = ECheck.eError
  the level of check on the input angles
Returns [number, string]
the third angle of the triangle in radian + string-for-log
- Defined in index.ts:182