Barrons AP Calculus

sin (π  + α)    =   −sin    α; cos  (π  + α)    =   −cos    α.

LAW OF  COSINES.    c   2   =   a^2 + b     2   −   2ab cos C.

LAW OF  SINES.  

The area    A   =    ab sin C.

GRAPHS  OF  TRIGONOMETRIC   FUNCTIONS

The four    functions   sketched    above,  sin,    cos,    csc,    and sec,    all have    period

2π.