Task: Text Categorization
Input (English): The dot product of two vectors over the product of their lengths gives this function of the angle between them. A law named for this function generalizes the Pythagorean theorem to non-right triangles; it uses two sides of a triangle and the included angle to find the length of the third side. (*) For 10 points, name this trigonometric ratio commonly calculated as "adjacent over hypotenuse" in right triangles.
Output (English): Science