From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/c/numeric%2Fmath%2Fcbrt.html | 71 ++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 devdocs/c/numeric%2Fmath%2Fcbrt.html (limited to 'devdocs/c/numeric%2Fmath%2Fcbrt.html') diff --git a/devdocs/c/numeric%2Fmath%2Fcbrt.html b/devdocs/c/numeric%2Fmath%2Fcbrt.html new file mode 100644 index 00000000..bb548272 --- /dev/null +++ b/devdocs/c/numeric%2Fmath%2Fcbrt.html @@ -0,0 +1,71 @@ +

cbrt, cbrtf, cbrtl

Defined in header <math.h> 
float       cbrtf( float arg );
+		 (1) (since C99) 
double      cbrt( double arg );
+		 (2) (since C99) 
long double cbrtl( long double arg );
+		 (3) (since C99)
Defined in header <tgmath.h> 
#define cbrt( arg )
+		 (4) (since C99)
+1-3) Computes the cube root of arg.
+4) Type-generic macro: If arg has type long double, cbrtl is called. Otherwise, if arg has integer type or the type double, cbrt is called. Otherwise, cbrtf is called.

Parameters

+ +
arg - floating point value

Return value

If no errors occur, the cube root of arg (\(\small{\sqrt[3]{arg} }\)3√arg), is returned.

+

If a range error occurs due to underflow, the correct result (after rounding) is returned.

+

Error handling

Errors are reported as specified in math_errhandling.

+

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

+

Notes

cbrt(arg) is not equivalent to pow(arg, 1.0/3) because the rational number \(\small{\frac1{3} }\)1/3 is typically not equal to 1.0/3 and std::pow cannot raise a negative base to a fractional exponent. Moreover, cbrt(arg) usually gives more accurate results than pow(arg, 1.0/3) (see example).

Example

#include <stdio.h>
+#include <float.h>
+#include <math.h>
+ 
+int main(void)
+{
+    printf("Normal use:\n"
+           "cbrt(729)      = %f\n", cbrt(729));
+    printf("cbrt(-0.125)   = %f\n", cbrt(-0.125));
+    printf("Special values:\n"
+           "cbrt(-0)       = %f\n", cbrt(-0.0));
+    printf("cbrt(+inf)     = %f\n", cbrt(INFINITY));
+    printf("Accuracy:\n"
+           "cbrt(343)      = %.*f\n", DBL_DECIMAL_DIG, cbrt(343));
+    printf("pow(343,1.0/3) = %.*f\n", DBL_DECIMAL_DIG, pow(343, 1.0/3));
+}

Possible output:

+
Normal use:
+cbrt(729)      = 9.000000
+cbrt(-0.125)   = -0.500000
+Special values:
+cbrt(-0)       = -0.000000
+cbrt(+inf)     = inf
+Accuracy:
+cbrt(343)      = 7.00000000000000000
+pow(343,1.0/3) = 6.99999999999999911

References

See also

+ + + +
+
(C99)(C99)
 computes a number raised to the given power (\(\small{x^y}\)xy)
(function)
+
(C99)(C99)
 computes square root (\(\small{\sqrt{x} }\)√x)
(function)
+
(C99)(C99)(C99)
 computes square root of the sum of the squares of two given numbers (\(\scriptsize{\sqrt{x^2+y^2} }\)√x2+y2)
(function)
C++ documentation for cbrt
+

+ © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
+ https://en.cppreference.com/w/c/numeric/math/cbrt +

+
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