This article brings you relevant knowledge aboutjavascript, which mainly introduces related issues about the Math object method. The Math object is a built-in object of JavaScript, providing a series of mathematical constants and mathematical Method, this object is not a constructor, so it cannot generate an instance. All properties and methods must be called on the Math object. Let’s take a look at it together. I hope it will be helpful to everyone.
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The Math object is a built-in JavaScript Object that provides a set of mathematical constants and mathematical methods.
This object is not a constructor, so an instance cannot be generated. All properties and methods must be called on the Math object.
new Math() // TypeError: object is not a function
The above code indicates that Math cannot be used as a constructor.
The Math object provides the following read-only mathematical constants.
E: constant e.
LN2: The natural logarithm of 2.
LN10: The natural logarithm of 10.
LOG2E: The base 2 logarithm of e.
LOG10E: The base 10 logarithm of e.
PI: Constant Pi.
SQRT1_2: The square root of 0.5.
SQRT2: The square root of 2.
The values of these constants are as follows.
Math.E // 2.718281828459045 Math.LN2 // 0.6931471805599453 Math.LN10 // 2.302585092994046 Math.LOG2E // 1.4426950408889634 Math.LOG10E // 0.4342944819032518 Math.PI // 3.141592653589793 Math.SQRT1_2 // 0.7071067811865476 Math.SQRT2 // 1.4142135623730951
The Math object provides the following mathematical methods.
round method
The round method is used for rounding.
Math.round(0.1) // 0 Math.round(0.5) // 1
Its operation results for negative values are slightly different from positive values, mainly reflected in the processing of .5.
Math.round(-1.1) // -1 Math.round(-1.5) // -1
abs method, max method, min method
abs method returns the absolute value of the parameter value.
Math.abs(1) // 1 Math.abs(-1) // 1
The max method returns the largest parameter, and the min method returns the smallest parameter.
Math.max(2, -1, 5) // 5 Math.min(2, -1, 5) // -1
floor method, ceil method
The floor method returns the largest integer less than the parameter value.
Math.floor(3.2) // 3 Math.floor(-3.2) // -4
The ceil method returns the smallest integer greater than the parameter value.
Math.ceil(3.2) // 4 Math.ceil(-3.2) // -3
pow method, sqrt method
power method returns the exponential value with the first parameter as the base and the second parameter as the power .
Math.pow(2, 2) // 4 Math.pow(2, 3) // 8
sqrt method returns the square root of the parameter value. If the argument is a negative value, NaN is returned.
Math.sqrt(4) // 2 Math.sqrt(-4) // NaN
log method, exp method
log method returns the natural logarithm value with e as the base.
Math.log(Math.E) // 1 Math.log(10) // 2.302585092994046
To find the logarithm of base 10, you can divide it by Math.LN10; to find the logarithm of base 2, you can divide it by Math.LN2.
Math.log(100)/Math.LN10 // 2 Math.log(8)/Math.LN2 // 3
The exp method returns the parameter power of the constant e.
Math.exp(1) // 2.718281828459045 Math.exp(3) // 20.085536923187668
random method
This method returns a pseudo-random number between 0 and 1, which may be equal to 0, but must be less than 1.
Math.random() // 0.7151307314634323 // 返回给定范围内的随机数 function getRandomArbitrary(min, max) { return Math.random() * (max - min) + min; } // 返回给定范围内的随机整数 function getRandomInt(min, max) { return Math.floor(Math.random() * (max - min + 1)) + min; }
Trigonometric function method
The sin method returns the sine of the parameter, the cos method returns the cosine of the parameter, and the tan method returns the tangent of the parameter.
Math.sin(0) // 0 Math.cos(0) // 1 Math.tan(0) // 0
The asin method returns the arc sine of the parameter, the acos method returns the arc cosine of the parameter, and the atan method returns the arc tangent of the parameter. The return values of these three methods are all radian values.
Math.asin(1) // 1.5707963267948966 Math.acos(1) // 0 Math.atan(1) // 0.7853981633974483
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