| A | B |
|---|
| Ratio identity tan | sin/cos |
| Ratio identity cot | cos/sin |
| Pythagorean identity sin/cos | sin squared + cos squared = 1 |
| Pythagorean identity sec/tan | 1 + tan squared = secant squared |
| Pythagorean identity csc/cot | 1 + cot squared = cosecant squared |
| Reciprocal Identity csc | csc = 1/sin |
| Reciprocal Identity cot | cot = 1/tan |
| Reciprocal Identity sec | sec = 1/cos |
| Odd-Even Identity sin | sin (- theta) = - sin theta |
| Odd-Even Identity cos | cos (- theta) = cos theta |
| Odd-Even Identity tan | tan (- theta) = - tan theta |
| Sum Identity Cos | Cos(A + B) = cosA cosB - sinA sinB |
| Difference Identity Cos | Cos (A - B) = cosA cosB + sinA sinB |
| Sum Identity Sin | Sin(A + B) = sinA cosB + cosA sinB |
| Difference Identity Sin | Sin(A - B) = sinA cosB - cosA sinB |
| Sum Identity Tan | tan (A + B) = tanA + tanB/1 - tanA tanB |
| Difference Identity Tan | tan (A - B) = tanA - tanB/1 + tanA tanB |
| Double Angle Identity Sin 2A | sin 2A = 2 sinA CosA |
| Double Angle Identity Tan 2A | tan 2A = 2 tanA/1 - tanA squared |
| Double Angle Identity#1 cos2A | #1cos 2A = cosA squared - sinA squared |
| Double Angle Identity#2 cos2A | #2cos 2A = 2 cosA squared - 1 |
| Double Angle Identity#3 cos2A | #3 cos 2A = 1 - 2 sinA squared |
| Half Angle Identity #1 tanA/2 | Tan A/2 = square root of [(1 - cosA)/(1 + cosA)] |
| Half Angle Identity #2 tanA/2 | tan A/2 = (1 - cosA)/sinA |
| Half Angle Identity #3 tanA/2 | tan A/2 = sinA /( 1 + cosA) |
| Half Angle Identity sinA/2 | square root of [(1 - cosA)/ 2] |
| Half Angle Identity cosA/2 | square root of [(1 + cosA)/2] |
