even function
function which is symmetric with respect to the vertical axis
constant function
mathematical function whose (output) value is the same for every input value
square function
function which maps a number to its square
hyperbolic cosine
hyperbolic function
zero function
function whose codomain contains only 0
cosine
trigonometric function; ratio between the lengths of the adjacent side and the hypotenuse in a right triangle
absolute value
nonnegative number with the same magnitude as a given real number