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education/math/MATH1220 (calc II)/Integration with Trig Identities.md

@@ -74,4 +74,12 @@ $$ \int\frac{3}{4+x^2}dx = \frac{3}{2}\arctan(\frac{x}{2}) + C $$
 | $\sin^2(x) + \cos^2(x) = 1$          |
 | $1 + \tan^2(x) = \sec^2(x)$          |
 | $1 + \cot^2(x) = \csc^2(x)$          |
-| $1 
+
+| Sum and Difference                                  |
+| --------------------------------------------------- |
+| $\sin(A \pm B) = \sin(A)\cos(B) \pm \cos(A)\sin(B)$ |
+| $\cos(A \pm B) = \cos(A)\cos(B) \mp \sin(A)\sin(B)$ |
+| $\sin(2x) = 2\sin(x)\cos(x)$                        |
+| $\cos(2x) = \cos^2(x) - \sin^2(x)$                  |
+| $\cos^2(x) = \frac{1}{2}(1 + \cos(2x)$              |
+|                                                     |