Cotangent is the ratio of the hypotenuse to the opposite side of an acute angle in a right triangle, which is expressed by csc (angle). Secant is the ratio of the hypotenuse of an acute angle to its adjacent side in a right triangle (that is, the hypotenuse of angle A is greater than its adjacent side), which is called the secant of acute angle.
Y = y = properties of secx:
1, domain, {x|x≠kπ+π/2, k∈Z}
2. Range, | secx | ≥ 1. That is, secx≥ 1 or secx ≤-1;
3.y=secx is an even function, that is, sec (-x) = secx. The image is symmetrical with respect to the y axis.