Mathematical symbol secant is secant, which comes from English secant. Mathematician Gillard first used this symbol in his book Trigonometry. In y=secx, any value of x that makes secx meaningful and its corresponding y value are taken as (x, y). The graph made in cartesian coordinate system is called the image of secx function, also called secx curve.

Extended data:

Properties of secant function:

1, domain, x cannot be equal to 90 degrees, 270 degrees, -90 degrees and -270 degrees; That is {x|x≠kπ+, k∈Z}.

2. the range of secx ≥1or secx ≤- 1 is (-∞,-1]∩[ 1, +∞).

3.y=secx is an even function, that is, sec (-θ) = secθ. The image is symmetrical with respect to the y axis.

4.y=secx is a periodic function with a period of 2kπ(k∈Z, k≠0), and the minimum positive period T=2π.