AP PreCalc Trig Identities

cos²(x)+sin²(x)

1

tan²(x)+1

sec²(x)

cot²(x)+1

csc²(x)

cos(a+b)

cos(a)cos(b)-sin(a)sin(b)

cos(a-b)

cos(a)cos(b)+sin(a)sin(b)

sin(a+b)

sin(a)cos(b)+cos(a)sin(b)

sin(a-b)

sin(a)cos(b)-cos(a)sin(b)

sin(2x)

2sin(x)cos(x)

cos(2x)

1-2sin²(x)

cos²(x)-sin²(x)

2cos²(x)-1

cos²(x)

(1+cos(2x))/2

sin²(x)

(1-cos(2x))/2

sin(x/2)

sqrt((1-cos(x))/2)

cos(x/2)

sqrt((cos(x)+1)/2)