Quadratic Formula 2 −± b b − 4ac x = 2a Trigonometric Identities 2 2 sin ( ) θ + cos ( ) θ =1 sin ( ) θ cos( ) θ tan ( ) θ = cot( ) θ = cos( ) θ sin ( ) θ 1 1 csc( ) θ = sec( ) θ = sin ( ) θ cos( ) θ Cubic Factorizations 3 3 2 2 a + b = ( a + b)(a − ab + b ) 3 3 2 2 a − b = ( a b − )(a + ab b + ) Probability P A(  B) = P A( ) + P B( ) − P A(  B) P A(  B) P AB ( ) = P B( ) Independence P A(  B) = P A( ) ( )  P B P AB ( ) = P A( ) Arithmetic Sequence an = a + d n( −1) 1 Arithmetic Series