Mathematical function library, the concrete realization of some mathematical calculation formulas is put in math.h, specifically:

1, trigonometric function

Double)； crime; sine

Double cos (double); cosine

Shuangtan (double); tangent

2. Inverse trigonometric function

double asin(double)； The result is between [-PI/2, PI/2]

Double acos (double); The result is between [0, PI]

Double (double); Arctangent (principal value), the result is between [-PI/2, PI/2]

double atan2 (double，double)； Arctangent (integer value), the result is between [-PI, PI]

3. Hyperbolic trigonometric functions

Double sinh (double);

Double cosh (double);

Double tanh (double);

4. Exponents and Logarithms

double frexp(double value，int * exp)； This is a method to split a value into a fractional part f and an exponential part exp (base 2), and return the fractional part f, that is, f * 2 exp. Where the value of f is in the range of 0.5~ 1.0 or 0.

double ldexp(double x，int exp)； This function is just the opposite of the frexp function above, and the return value is x * 2 exp.

double modf(double value，double * iptr)； Split a value and return its fractional part, with iptr pointing to the integer part.

Double; Logarithm based on e

double log 10(double)； Logarithm based on 10

Double power (double x, double y); Calculate the y power with x as the base.

Floating point powf (floating point x, floating point y); This function is the same as pow, except that the input and output are floating-point numbers.

Double exp (double); Find the power of natural number e

double sqrt(double)； extract a root

5, rounding

Double ceiling (double); Rounds up and returns the smallest integer not less than x.

Double floor (double); Take the integer down and return the largest integer not greater than x, which is the Gaussian function [x]

6. Absolute value

int ABS(int I)； Find the absolute value of an integer

Double wafer factory (double); Absolute value of realistic type

Double cab (complex structure Znum); Find the absolute value of a complex number

7. Standardized floating-point numbers

double frexp (double f，int * p)； Standardized floating-point number, f = x * 2^p, f is known to find x, p (x is between [0.5, 1]).

double ldexp (double x，int p)； Contrary to frexp, it is known that x and p find f.

8. Rounding and rounding

double modf (double，double *)； Returns the integer part of a parameter through a pointer, and returns the decimal part.

double fmod (double，double)； Returns the remainder of the division of two parameters.