Conversion of radians and angles in JavaScript

弧度 = 角度 * Math.PI / 180
角度 = 弧度 * 180 / Math.PI

In the JavaScript Math object:

The sin () method returns the sine of a number.
The tan () method returns a number that represents the tangent of a corner.

Math.sin(x)Math.tan(x)

Parameter x is required. A corner expressed in radians. Multiply the angle by 0.017453293 (2pi/360) to convert to radians (that is, angle * math.pi/180).

The Cos () method returns the cosine of a number.

Math.cos(x)

Parameter x is required. Must be a numeric value.

The ASIN () method returns the inverse chord value of a number.
The ACOs () method returns the inverse cosine of a number.

Math.asin(x)Math.acos(x)

Parameter x is required. Must be a numeric value between X∈[-1, 1].

The Atan () method returns the inverse tangent value of a number.

Math.atan(x)

Parameter x is required. Must be a numeric value.

The POW () method returns the value of the Y-power of X.

Math.pow(x,y)

Parameter x is required. Base Must be a number.
Parameter y is required. The power number. Must be a number.

The sqrt () method returns the square root of a number.

Math.sqrt(x)

Parameter x is required. Must be a number greater than or equal to 0.

• Review Trigonometric functions

Sine (sin): to edge ratio hypotenuse SinA = A/C

Cosine (COS): Adjacent edge ratio hypotenuse CosA = b/c

Tangent (tan): to edge adjacent edge Tana = A/b

Cotangent (Cot): Adjacent edge-to-edge CotA = b/a

Secant (sec): hypotenuse adjacent Edge

Residual cutting (CSC): hypotenuse ratio to edge

• Sine theorem

sina/a = sinb/b = sinc/c

Can also be expressed as:

A/sina = B/SINB = C/sinc = 2R (R is the circumscribed circle radius of the triangle)

The trigonometric sine theorem can be used to obtain the area of a triangle:

S = 1/2absinc = 1/2bcsina = 1/2acsinb

• Cosine theorem

a2 = b2 + C2-2BC CosA
b2 = A2 + c2-2ac Cosb
C2 = a2 + b2-2ab CosC

Can also be expressed as:

Cosa= (C2 +b2-a2)/2BC
cosb= (A2 +c2-b2)/2AC
cosc= (A2 +b2-c2)/2ab

First cosine theorem:

A = b Cosc + c COSB
b = C Cosa + a Cosc
c = a COSB + b cosa

• Tangent theorem

(A + B)/(a) = tan ((A + B)/2)/tan ((-a)/2)

Conversion of radians and angles in JavaScript