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# Math

The Math module contains module functions for basic trigonometric and transcendental functions. See class Float for a list of constants that define Ruby's floating point accuracy.

E
PI

### Public Class Methods

acos(x) => float click to toggle source

Computes the arc cosine of x. Returns 0..PI.

static VALUE
math_acos(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = acos(RFLOAT(x)->value);
domain_check(d, "acos");
return rb_float_new(d);
}

acosh(x) => float click to toggle source

Computes the inverse hyperbolic cosine of x.

static VALUE
math_acosh(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = acosh(RFLOAT(x)->value);
domain_check(d, "acosh");
return rb_float_new(d);
}

asin(x) => float click to toggle source

Computes the arc sine of x. Returns -{PI/2} .. {PI/2}.

static VALUE
math_asin(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = asin(RFLOAT(x)->value);
domain_check(d, "asin");
return rb_float_new(d);
}

asinh(x) => float click to toggle source

Computes the inverse hyperbolic sine of x.

static VALUE
math_asinh(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(asinh(RFLOAT(x)->value));
}

atan(x) => float click to toggle source

Computes the arc tangent of x. Returns -{PI/2} .. {PI/2}.

static VALUE
math_atan(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(atan(RFLOAT(x)->value));
}

atan2(y, x) => float click to toggle source

Computes the arc tangent given y and x. Returns -PI..PI.

static VALUE
math_atan2(obj, y, x)
VALUE obj, x, y;
{
Need_Float2(y, x);
return rb_float_new(atan2(RFLOAT(y)->value, RFLOAT(x)->value));
}

atanh(x) => float click to toggle source

Computes the inverse hyperbolic tangent of x.

static VALUE
math_atanh(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = atanh(RFLOAT(x)->value);
domain_check(d, "atanh");
return rb_float_new(d);
}

cos(x) => float click to toggle source

Computes the cosine of x (expressed in radians). Returns -1..1.

static VALUE
math_cos(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(cos(RFLOAT(x)->value));
}

cosh(x) => float click to toggle source

Computes the hyperbolic cosine of x (expressed in radians).

static VALUE
math_cosh(obj, x)
VALUE obj, x;
{
Need_Float(x);

return rb_float_new(cosh(RFLOAT(x)->value));
}

erf(x) => float click to toggle source

Calculates the error function of x.

static VALUE
math_erf(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(erf(RFLOAT(x)->value));
}

erfc(x) => float click to toggle source

Calculates the complementary error function of x.

static VALUE
math_erfc(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(erfc(RFLOAT(x)->value));
}

exp(x) => float click to toggle source

Returns e**x.

static VALUE
math_exp(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(exp(RFLOAT(x)->value));
}

frexp(numeric) => [ fraction, exponent ] click to toggle source

Returns a two-element array containing the normalized fraction (a Float) and exponent (a Fixnum) of numeric.

fraction, exponent = Math.frexp(1234)   #=> [0.6025390625, 11]
fraction * 2**exponent                  #=> 1234.0

static VALUE
math_frexp(obj, x)
VALUE obj, x;
{
double d;
int exp;

Need_Float(x);

d = frexp(RFLOAT(x)->value, &exp);
return rb_assoc_new(rb_float_new(d), INT2NUM(exp));
}

hypot(x, y) => float click to toggle source

Returns sqrt(x**2 + y**2), the hypotenuse of a right-angled triangle with sides x and y.

Math.hypot(3, 4)   #=> 5.0

static VALUE
math_hypot(obj, x, y)
VALUE obj, x, y;
{
Need_Float2(x, y);
return rb_float_new(hypot(RFLOAT(x)->value, RFLOAT(y)->value));
}

ldexp(flt, int) → float click to toggle source

Returns the value of flt*(2**int).

fraction, exponent = Math.frexp(1234)
Math.ldexp(fraction, exponent)   #=> 1234.0

static VALUE
math_ldexp(obj, x, n)
VALUE obj, x, n;
{
Need_Float(x);
return rb_float_new(ldexp(RFLOAT(x)->value, NUM2INT(n)));
}

log(numeric) => float click to toggle source

Returns the natural logarithm of numeric.

static VALUE
math_log(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = log(RFLOAT(x)->value);
domain_check(d, "log");
return rb_float_new(d);
}

log10(numeric) => float click to toggle source

Returns the base 10 logarithm of numeric.

static VALUE
math_log10(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = log10(RFLOAT(x)->value);
domain_check(d, "log10");
return rb_float_new(d);
}

sin(x) => float click to toggle source

Computes the sine of x (expressed in radians). Returns -1..1.

static VALUE
math_sin(obj, x)
VALUE obj, x;
{
Need_Float(x);

return rb_float_new(sin(RFLOAT(x)->value));
}

sinh(x) => float click to toggle source

Computes the hyperbolic sine of x (expressed in radians).

static VALUE
math_sinh(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(sinh(RFLOAT(x)->value));
}

sqrt(numeric) => float click to toggle source

Returns the non-negative square root of numeric.

static VALUE
math_sqrt(obj, x)
VALUE obj, x;
{
double d;

Need_Float(x);
errno = 0;
d = sqrt(RFLOAT(x)->value);
domain_check(d, "sqrt");
return rb_float_new(d);
}

tan(x) => float click to toggle source

Returns the tangent of x (expressed in radians).

static VALUE
math_tan(obj, x)
VALUE obj, x;
{
Need_Float(x);

return rb_float_new(tan(RFLOAT(x)->value));
}

tanh() => float click to toggle source

Computes the hyperbolic tangent of x (expressed in radians).

static VALUE
math_tanh(obj, x)
VALUE obj, x;
{
Need_Float(x);
return rb_float_new(tanh(RFLOAT(x)->value));
}