Ask what trigonometric function is required for work

It is a function of sine, cosine, etc. about angles.

In mathematics, trigonometric functions (also known as circular functions) are functions of angles; They are important in studying triangles and modeling periodic phenomena and many other applications. Trigonometric function is usually defined as the ratio of the two sides of a right triangle containing this angle, and can also be defined equivalently as the length of various line segments on a unit circle. More modern definitions express them as infinite series or solutions to specific differential equations, allowing them to extend to arbitrary positive and negative values, even complex values.

Trigonometric functions belong to a class of functions in mathematics that are transcendental functions in elementary functions. They are essentially a mapping between a set of arbitrary angles and a set of variables with a ratio. Because trigonometric functions are periodic, they do not have an inverse function in the sense of a monographic function (also known as a monotonic function).

Trigonometric functions have important applications in complex numbers and are commonly used tools in physics.

Trigonometric functions are generally used to calculate the edges of unknown lengths and unknown angles in triangles (usually right triangles) and have a wide range of uses in navigation systems, engineering, and physics. A common use in elementary physics is to convert vectors into Cartesian coordinate systems. There are 6 trigonometric functions commonly used in modern times, among which sin and cos are also commonly used to simulate periodic function phenomena, such as sound waves and light waves, the position and speed of harmonic oscillators, light intensity and day length, average temperature changes in the past year, and so on. **。

The function means that letters, like mailboxes, are one-to-one. Each angle of the trigonometric function corresponds to the value of the function. For example, sin30=, which means that in a right triangle, the side opposite by the 30 degree angle is half of the hypotenuse, and the one-to-one correspondence, sin30 cannot be equal to, nor can it be equal to or other numbers, sin30 can only be in short, not only trigonometric functions, including primary functions, quadratic functions, all pay attention to the correspondence of functions, that is, the correspondence of independent variables and dependent variables.

The original background of trigonometric functions was formed in triangles, such as the definition of sine in junior high school: the ratio of the opposite side of an acute angle to the hypotenuse in a right triangle is called sinusoidal.

Trigonometric functions should be functions in triangles.

Trigonometric functions are a class of functions in mathematics that belong to the transcendental functions of elementary functions. Their essence is a mapping between the variables of a set of arbitrary auspicious angles of attack and a set of ratios.

The trigonometric function of the universal friend is defined in a planar Cartesian coordinate system, and its domain is defined as the entire field of real numbers. Another definition is in a right triangle, but not completely. Modern mathematics describes them as the limits of an infinite series of numbers and the solution of differential equations, extending their definition to complex systems.

There are six basic functions: sine function, cosine function, tangent function, cotangent function, secant function, cosecant function.

The sine function sin = y r

Cosine function cos =x r

Tangent function tan =y x

Cotangent function cot = x y

The secant function sec = r x

Cosecant function csc =r y

Isoangular trigonometric functions (function relationship extension).

1) Squared Relationship:

sin^2(α)cos^2(α)1

tan^2(α)1=sec^2(α)

cot^2(α)1=csc^2(α)

2) Product Relationship:

sin = tan *cos cos =cot *sin tan =sin *sec cot =cos *csc sec =tan *csc csc =sec *cot 3) reciprocal relation:

tanα·cotα=1

sinα·cscα=1

cosα·secα=1

Equation for identity deformation.

Trigonometric function of the sum and difference of two angles:

cos(α+cosα·cosβ-sinα·sinβcos(α-cosα·cosβ+sinα·sinβsin(α±sinα·cosβ±cosα·sinβtan(α+tanα+tanβ)/1-tanα·tanβ)tan(α-tanα-tanβ)/1+tanα·tanβ)

For example, Bai Ming:

Elementary stage. A right-angled three-du-angle has been measured to be the length of an acute angle and a right-angled edge, but the other two sides cannot be directly measured for some reason. In this case, we can use trigonometric functions to find the lengths of the other two sides.

Advanced stage. Using the Fourier transform theory, we can turn seemingly chaotic functions into "sums of a series of trigonometric functions", so as to see the clouds and get to the point. This move makes ordinary people feel incredible.

According to the trigonometric relationship, sin(90°- cos (0 90°), cos90°=sin0°=0, and cos0°=sin90°=1. In a right-angled triangle, sin = opposite side hypotenuse, sin90° = opposite side hypotenuse = hypotenuse hypotenuse = 1