WE STUMBLE INTO OUR LIVES, REACH FOR A HAND TO HOLD.

sin²q+ cos²q=1
sin(A+B)=sin(A)cos(B)+cos(A)sin(B)
sin(A-B)=sin(A)cos(B)-cos(A)sin(B)
cos(A+B)=cos(A)cos(B)-sin(A)sin(B)
cos(A-B)=cos(A)cos(B)+sin(A)sin(B)
tan(A+B)=(tan(A)+tan(B))/(1-tan(A)tan(B))
tan(A-B)=(tan(A)-tan(B))/(1+tan(A)tan(B))
sin(2A)=2sin(A)cos(A)
cos(2A)=cos2(A)-sin2(A)
tan(2A)=2tan(A)/(1-tan2(A))
sin(A)+sin(B)=2sin{(A+B)/2}cos{(A-B)/2}
sin(A)-sin(B)=2cos{(A+B)/2}sin{(A-B)/2}
cos(A)+cos(B)=2cos{(A+B)/2}cos{(A-B)/2}
cos(A)-cos(B)=-2sin{(A+B)/2}sin{(A-B)/2}

That's it, all I can say tonight.