Module: (Python) Real numbers


Problem

9 /11


Operations with real numbers. Module math

Theory Click to read/hide

When working with real numbers, you can use the familiar math module, which contains a large number of built-in functions.
When solving problems, one often has to round real numbers to the nearest integer values. There are two functions for this.

REMEMBER
1
function int (x) - discards the fractional part of the real number x
2 function round (x) - rounds the real number x to the nearest integer (if the fractional part of the number is 0.5, then the number is rounded to the nearest even number)

Приведем наиболее полезные функции, содержащиеся в модуле math.

Функция Описание
Округление
int(x) Rounds a number to zero. This is a standard function, you do not need to connect the math module to use it.
round(x) Rounds a number to the nearest integer. If the fractional part of a number is 0.5, then the number is rounded to the nearest even number.
round(x, n) Rounds the number x to n characters after the period. This is a standard function, you do not need to connect the math module to use it.
floor(x) Rounds the number down: floor(1.5) == 1floor(-1.5) == -2
ceil(x) Rounds the number up: ceil(1.5) == 2ceil(-1.5) == -1
abs(x) Module (absolute value). This is a standard feature.
Корни, логарифмы
sqrt(x) Square root. Using: math.sqrt(x).
Example:
print(math.sqrt(4))
output: 2.0
log(x) The natural logarithm. When called as math.log(x, b) returns base b logarithm.
e The base of natural logarithms e = 2,71828...
Тригонометрия
sin(x) The sine of the angle given in radians
cos(x) The cosine of the angle given in radians
tan(x) Radius tangent
asin(x) Arcsine, returns a value in radians
acos(x) Arccosine, returns the value in radians
atan(x) Arc tangent, returns the value in radians
atan2(y, x) Polar angle (in radians) of the point with coordinates (x, y).
degrees(x) Converts an angle specified in radians to degrees.
radians(x) Converts an angle specified in degrees to radians.
pi Constant π = 3.1415...

Problem

Write a program that calculates the square root of a number entered from the keyboard, accurate to three decimal places.
The input is a real number.
Example
Input
25.
Output
5.000