找到 csc 270° 的准确值
三角学是一门数学学科,研究直角三角形的边长和角之间的关系。三角函数,也称为测角函数、角函数或圆函数,是建立角度与直角三角形两条边之比之间关系的函数。六个主要的三角函数是正弦、余弦、正切、余切、正割或余割。
Angles defined by the ratios of trigonometric functions are known as trigonometry angles. Trigonometric angles represent trigonometric functions. The value of the angle can be anywhere between 0-360°.
如上图中的直角三角形所示:
- 斜边:与直角相对的边是斜边,它是直角三角形中最长的边,与90°角相对。
- 底:角 C 所在的一侧称为底。
- 垂直:考虑角度 C 的对边。
三角函数
三角函数有 6 个基本的三角函数,它们是正弦、余弦、正切、余割、正割和余切。现在让我们看看三角函数。六个三角函数如下,
- 正弦:它被定义为垂直和斜边的比率,它表示为 sin θ
- 余弦:定义为底边与斜边的比值,表示为 cos θ
- 正切:它被定义为一个角度的正弦和余弦之比。因此,切线的定义是垂直与底的比值,并表示为 tan θ
- cosecant:它是 sin θ 的倒数,表示为 cosec θ。
- 割线:它是 cos θ 的倒数,表示为 sec θ。
- cotangent:它是 tan θ 的倒数,表示为 cot θ。
According to above image, Trigonometric Ratios are
1) Sin θ = Perpendicular / Hypotenuse
= AB/AC
2) Cosine θ = Base / Hypotenuse
= BC / AC
3) Tangent θ = Perpendicular / Base
= AB / BC
4) Cosecant θ = Hypotenuse / Perpendicular
= AC/AB
5) Secant θ = Hypotenuse / Base
= AC/BC
6) Cotangent θ = Base / Perpendicular
= BC/AB
互惠身份
Sin θ = 1/ Cosec θ OR Cosec θ = 1/ Sin θ
Cos θ = 1/ Sec θ OR Sec θ = 1 / Cos θ
Cot θ = 1 / Tan θ OR Tan θ = 1 / Cot θ
Cot θ = Cos θ / Sin θ OR Tan θ = Sin θ / Cos θ
Tan θ.Cot θ = 1
三角比值 0° 30° 45° 60° 90° 0 1/2 1/√2 √3/2 1 1 √3/2 1/√2 1/2 0 0 1/√3 1 √3 Not Defined Not Defined 2 √2 2/√3 1 1 2/√3 √2 2 Not Defined Not Defined √3 1 1/√3 0 Sin θ Cos θ Tan θ Cosec θ Sec θ Cot θ
补角和补角的三角恒等式
- 互补角:和等于90°的一对角
- 补角:和等于 180° 的一对角
互补角的恒等式是
- sin (90° – θ) = cos θ
- cos (90° – θ) = sin θ
- tan (90° – θ) = 婴儿床 θ
- 婴儿床 (90° – θ) = tan θ
- 秒 (90° – θ) = cosec θ
- cosec (90° – θ) = 秒 θ
补角的恒等式
- sin (180° – θ) = sin θ
- cos (180° – θ) = – cos θ
- tan (180° – θ) = – tan θ
- 婴儿床 (180° – θ) = – 婴儿床 θ
- 秒 (180° – θ) = – 秒 θ
- cosec (180° – θ) = – cosec θ
这是三角函数的象限
找到 csc 270° 的准确值
解决方案:
Here cosec is positive only in 1st and 2nd Quadrant.
270° does not lies in 1st and 2nd Quadrant.
Therefore cosec (360° – θ) = – cosec θ
cosec (270°) = cosec (360° – 90°)
cosec (270°) = – cosec (90°)
cosec (270°) = – 1 { as per the trigonometry value table cosec90° = 1 }
Therefore, the exact value of cosec (270°) is – 1 .
类似问题
问题 1:sin 270 的确切值是多少?
解决方案:
Here sin is positive only in 1st and 2nd Quadrant.
270° does not lies in 1st and 2nd Quadrant.
therefore sin (360° – θ) = – sin θ
sin (270°) = sin (360° – 90°)
sin (270°) = – sin (90°)
sin (270°) = – 1
So the exact value of sin 270 is -1
问题 2:tan 270 的确切值是多少?
解决方案:
Here tan is positive only in 1st and 3rd Quadrant.
270° lies in 3rd Quadrant.
therefore tan (360° – θ) = tan θ
tan (270°) = tan (360° – 90°)
tan (270°) = tan (90°)
tan (270°) = not defined { as per the trigonometry value table }
So the exact value of tan 270 is not defined.
问题3:cos 270的确切值是多少?
解决方案:
Here cos is positive only in 1st and 4th Quadrant.
270° lies in 3rd Quadrant.
Therefore cos(360° – θ) = – cos θ
cos(270°) = cos(360° – 90°)
cos(270°) = -cos(90°)
cos (270°) = 0 { as per the trigonometry value table }
So the exact value of cos 270 is 0 .