How to find trigonometric functions in javascript

In mathematics, trigonometric functions are a frequently occurring type of function that can help us calculate the side lengths, angles, heights, etc. of a triangle. In computer programming, JavaScript also provides some built-in trigonometric functions to help developers perform related calculations. In this article, we will introduce trigonometric functions in JavaScript and their usage.

JavaScript trigonometric functions can be called using the static methods of the Math object. This object provides sin, cos, tan, asin, acos, atan and other methods, corresponding to the sine, cosine, tangent, arcsine, arccosine and arctangent functions respectively. Below we will introduce each function in detail.

1. Sine function (sin)

The sine function is a periodic function with a value ranging from -1 to 1. In JavaScript, we can calculate the sine of an angle through the Math.sin() method. For example, calculate the sine of a 30-degree angle:

let sinValue = Math.sin(30 * Math.PI / 180); // 返回0.5

Among them, Math.PI represents pi, and its value is approximately 3.14159. Since the parameter received by the sin method is a radian value, we need to convert the angle value into a radian value for calculation. In the above code, we convert 30 degrees into radians and pass it in as the parameter of the sin method. The calculation result is 0.5, that is, the sine of an angle of 30 degrees is 0.5.

2. Cosine function (cos)

The cosine function is also a periodic function, and its value range is also between -1 and 1. In JavaScript, we can calculate the cosine of an angle through the Math.cos() method. For example, to calculate the cosine of a 45-degree angle:

let cosValue = Math.cos(45 * Math.PI / 180); // 返回0.707

Similar to the sin method, we need to convert the angle value into a radian value for calculation. In the above code, we convert 45 degrees into radians and pass it in as a parameter of the cos method. The calculated result is 0.707, that is, the cosine of a 45-degree angle is 0.707.

3. tangent function (tan)

The tangent function is also a periodic function, and its value range is not limited. In JavaScript, we can calculate the tangent of an angle through the Math.tan() method. For example, to calculate the tangent of a 60-degree angle:

let tanValue = Math.tan(60 * Math.PI / 180); // 返回1.732

Similarly, we need to convert the angle value into a radian value for calculation. In the above code, we convert 60 degrees into radians and pass it in as a parameter of the tan method. The calculation result is 1.732, that is, the tangent value of the 60-degree angle is 1.732.

4. Arcsine function (asin)

The arcsine function is the inverse function of the sine function. In JavaScript, a sine value can be calculated through the Math.asin() method corresponding angle. For example, to calculate the angle whose sine value is 0.5:

let asinValue = Math.asin(0.5) * 180 / Math.PI; // 返回30

Here, we take 0.5 as the parameter of the asin method, calculate the radian value of the angle whose sine value is 0.5, and convert it into an angle value. The calculation result is 30, that is, the angle with a sine value of 0.5 is 30 degrees.

Note: Since the arcsine function is a single-valued function, its value range is [-π/2, π/2]. If the parameter passed in is outside this range, NaN will be returned.

5. Inverse cosine function (acos)

The inverse cosine function is the inverse function of the cosine function. In JavaScript, a cosine value can be calculated through the Math.acos() method corresponding angle. For example, to calculate the angle whose cosine value is 0.5:

let acosValue = Math.acos(0.5) * 180 / Math.PI; // 返回60

Similar to the arcsine function, we use 0.5 as the parameter of the acos method to calculate the radian value of the angle whose cosine value is 0.5 and convert it to an angle value . The calculation result is 60, that is, the angle with a cosine value of 0.5 is 60 degrees.

Note: Since the inverse cosine function is a single-valued function, its value range is [0, π]. If the parameter passed in is outside this range, NaN will be returned.

6. Arctangent function (atan)

The arctangent function is the inverse function of the tangent function. In JavaScript, a tangent value can be calculated through the Math.atan() method corresponding angle. For example, to calculate the angle whose tangent value is 1.732:

let atanValue = Math.atan(1.732) * 180 / Math.PI; // 返回60

Similarly, we use 1.732 as the parameter of the atan method, calculate the radian value of the angle whose tangent value is 1.732, and convert it to an angle value. The calculation result is 60, that is, the angle with a tangent value of 1.732 is 60 degrees.

The above is a detailed introduction to the six trigonometric functions of JavaScript and their usage. Mastering the use of these functions can help developers calculate triangle-related problems more conveniently and quickly.

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