Trigonometric Identities

Notes:

Reciprocal identities:

  • tan(x) = 1 / cot(x)

  • sec(x) = 1 / cos(x)

  • csc(x) = 1/ sin(x)

  • tan(x) = sin(x) / cos(x)

  • Cot(x) = cos(x) / sin(x)

Pythagorean Identities:

  • Sin2(x) + cos2(x) = 1

  • Tan2(x) + 1 = sec2(x)

  • 1 + cot2(x) = csc2(x)

Odd-Even Identities:

  • sin(-x) = -sin(x)

  • tan(-x) = -tan(x)

  • cot(-x) = -cot(x)

  • csc(-x) = -csc(x)

—

  • cos(-x) = cos(x)

  • sec(-x) = sec(x)

Cofunction Identities:

  • cos(ø) = sin((π / 2) - ø)

  • cot(ø) = tan((π / 2) - ø)

  • csc(ø) = sec((π / 2) - ø)

The rest of the notes are just example problems, check my math problem generator!