Secant refers to a right-angled triangle, and the ratio of the hypotenuse of an acute angle to the adjacent side is called secant of an acute angle, which is expressed by sec (angle). Secant is the reciprocal of cosine function.

Mathematical symbol secant is secant, which comes from English secant. Mathematician Gillard first used this symbol in his book Trigonometry.

nature

1, secant curve

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.

2. Functional attributes

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

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

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