secant

IPA/ˈsiː.kənt/
IPA/ˈsiː.kənt/

secant — noun

  • secantsingular
  • secantsplural

1. In a right triangle, when you divide the hypotenuse by the side beside a chosen

1.名詞C2
釋義

In a right triangle, when you divide the hypotenuse by the side beside a chosen acute angle, the result is the secant of that angle. In trigonometry, the function sec θ equals 1 over the cosine of the same angle.

例句

Wei found the secant of 30° by dividing the hypotenuse by the adjacent side.

secant + of + angle for trigonometric ratio

The secant of 60° equals 2, so the hypotenuse is twice the length of the adjacent side.

文法句型

the secant of [angle]

sec [angle]

用法筆記

In mathematical notation, a secant value is usually written as "sec" followed by the angle, for example sec 30° or sec(π/4). This sense is almost always used with the definite article when describing the function in general: "the secant of 30°".

常見錯誤

❌The secant of 30° is 0.5
✅The secant of 30° is about 1.15
💡Secant is the reciprocal of cosine; cos 30° ≈ 0.866, so sec 30° = 1/0.866 ≈ 1.15, not 0.5.
❌Secant is the same as inverse cosine (arccos)
✅Secant is the reciprocal of cosine, not the inverse function
💡Secant is 1/cos, which is different from arccos (the angle whose cosine is a given number).

2. In geometry, any line that cuts a curve or shape in two or more different places

2.名詞C2
釋義

In geometry, any line that cuts a curve or shape in two or more different places. In circle geometry, a secant enters and exits the circle at two distinct points on its circumference.

例句

Kwame drew a secant through the circle, marking both points where it crossed the edge.

a secant through [shape]

A tangent touches a circle once, but a secant crosses it at two points.

反義詞
  • tangent

    A tangent touches a curve at one point; a secant crosses at two or more points.

文法句型

a secant through [shape]

draw a secant

用法筆記

Often contrasted with tangent, which touches a curve at only one point. A secant that crosses a circle at two points can be seen as a chord extended in both directions beyond the circle's edge.

常見錯誤

❌A secant touches a circle at one point
✅A secant crosses a circle at two points
💡A line that touches at one point is called a tangent, not a secant.