Arccosine |
The arccosine is the angle whose cosine is the argument. |

Arcsine |
The arcsine is the angle whose sine is the argument. |

Arctangent |
The arctangent is the angle whose tangent is the argument. |

Cosine |
The cosine of an angle is the ratio of two sides of a right triangle. The ratio is the length of the side adjacent to the angle divided by the length of the hypotenuse. |

Sine |
The sine of an angle is the ratio of two sides of a right triangle. The ratio is the length of the side opposite to the angle divided by the length of the hypotenuse. |

Tangent |
The tangent of an angle is the ratio of two sides of a right triangle. The ratio is the length of the side opposite to the angle divided by the length of the side adjacent to the angle. |