Uncommon sum-diff/double angle, power-reducing/half angle, StP, PtS Original Alphabetical Study all 12 terms Study 0 termterms only (tan(a)+tan(b))/(1-tan(a)tan(b)) tan(a+b) (tan(a)-tan(b))/(1+tan(a)tan(b)) tan(a-b) 2tan(a)/(1-tan²(a)) tan(2a) (1-cos(2a))/2 sin²(a) (1+cos(2a))/2 cos²(a) 2sin((a+b)/2)cos((a-b)/2) sin(a)+sin(b) 2cos((a+b)/2)sin((a-b)/2) sin(a)-sin(b) 2cos((a+b)/2)cos((a-b)/2) cos(a)+cos(b) -2sin((a+b)/2)sin((a-b)/2) cos(a)-cos(b) (cos(a-b)-cos(a+b))/2 sin(a)sin(b) (cos(a-b)+cos(a+b))/2 cos(a)cos(b) (sin(a+b)+sin(a-b))/2 sin(a)cos(b)

(tan(a)+tan(b))/(1-tan(a)tan(b)) tan(a+b) (tan(a)-tan(b))/(1+tan(a)tan(b)) tan(a-b) 2tan(a)/(1-tan²(a)) tan(2a) (1-cos(2a))/2 sin²(a) (1+cos(2a))/2 cos²(a) 2sin((a+b)/2)cos((a-b)/2) sin(a)+sin(b) 2cos((a+b)/2)sin((a-b)/2) sin(a)-sin(b) 2cos((a+b)/2)cos((a-b)/2) cos(a)+cos(b) -2sin((a+b)/2)sin((a-b)/2) cos(a)-cos(b) (cos(a-b)-cos(a+b))/2 sin(a)sin(b) (cos(a-b)+cos(a+b))/2 cos(a)cos(b) (sin(a+b)+sin(a-b))/2 sin(a)cos(b)