# 15.1 The math and cmath Modules

The math module supplies mathematical functions on floating-point numbers, while the cmath module supplies equivalent functions on complex numbers. For example, math.sqrt(-1) raises an exception, but cmath.sqrt(-1) returns 1j.

Each module also exposes two attributes of type float bound to the values of fundamental mathematical constants, pi and e.

 acos math and cmath

 `acos(x)`

Returns the arccosine of x in radians.

 acosh cmath only

 `acosh(x)`

Returns the arc hyperbolic cosine of x in radians.

 asin math and cmath

 `asin(x)`

Returns the arcsine of x in radians.

 asinh cmath only

 `asinh(x)`

Returns the arc hyperbolic sine of x in radians.

 atan math and cmath

 `atan(x)`

Returns the arctangent of x in radians.

 atanh cmath only

 `atanh(x)`

Returns the arc hyperbolic tangent of x in radians.

 atan2 math only

 `atan2(y,x)`

Like atan(y/x), except that when x equals 0, atan2 returns pi/2, while dividing by x would raise ZeroDivisionError.

 ceil math only

 `ceil(x)`

Returns the lowest integer i such that i is greater than or equal to x as a floating-point value.

 cos math and cmath

 `cos(x)`

Returns the cosine of x in radians.

 cosh math and cmath

 `cosh(x)`

Returns the hyperbolic cosine of x in radians.

 e math and cmath

The mathematical constant e.

 exp math and cmath

 `exp(x)`

Returns e**x.

 fabs math only

 `fabs(x)`

Returns the absolute value of x.

 floor math only

 `floor(x)`

Returns the highest integer i such that i is less than or equal to x as a floating-point value.

 fmod math only

 `fmod(x,y)`

Returns x%y (on most platforms).

 frexp math only

 `frexp(x)`

Returns a pair (m,e) with the mantissa and exponent of x. m is a floating-point number and e is an integer such that x= =m*(2**e) and 0.5<=abs(m)<1, except that frexp(0) returns (0.0,0).

 hypot math only

 `hypot(x,y)`

Returns sqrt(x*x+y*y).

 ldexp math only

 `ldexp(x,i)`

Returns x*(2**i).

 log math and cmath

 `log(x)`

Returns the natural logarithm of x.

 log10 math and cmath

 `log10(x)`

Returns the base-10 logarithm of x.

 modf math only

 `modf(x)`

Returns a pair (f,i) with fractional and integer parts of x, each a floating-point value with the same sign as x.

 pi math and cmath

The mathematical constant .

 pow math only

 `pow(x,y)`

Returns x**y.

 sin math and cmath

 `sin(x)`

Returns the sine of x in radians.

 sinh math and cmath

 `sinh(x)`

Returns the hyperbolic sine of x in radians.

 sqrt math and cmath

 `sqrt(x)`

Returns the square root of x.

 tan math and cmath

 `tan(x)`

Returns the tangent of x in radians.

 tanh math and cmath

 `tanh(x)`

Returns the hyperbolic tangent of x in radians.

 Part I: Getting Started with Python
 Part II: Core Python Language and Built-ins
 Part IV: Network and Web Programming
 Part V: Extending and Embedding