// logarithmic convenience constants -- these can be accessed through library
// calls, but they're commonly used enough to warrant convenience constants
Math
.
LN2
// the natural logarithm of 2: ~0.693
Math
.
LN10
// the natural logarithm of 10: ~2.303
Math
.
LOG2E
// the base 2 logarithm of Math.E: ~1.433
Math
.
LOG10E
// the base 10 logarithm of Math.E: 0.434
// algebraic convenience constants
Math
.
SQRT1_2
// the square root of 1/2: ~0.707
Math
.
SQRT2
// the square root of 2: ~1.414
Algebraic Functions
Exponentiation
The basic exponentiation function is
Math.pow
, and there are convenience functions
for square root, cube root, and powers of e, as shown in
Table 16-1. Exponentiation functions
Function
Description
Examples
Math.pow(x, y)
x
y
Math
.
pow
(
2
,
3
)
// 8
Math
.
pow
(
1.7
,
2.3
)
// ~3.39
Math.sqrt(x)
x
Equivalent to
Math.pow(x, 0.5)
Math
.
sqrt
(
16
)
// 4
Math
.
sqrt
(
15.5
)
// ~3.94
Math.cbrt(x)
Cube root of x
Equivalent to
Math.pow(x,
1/3)
Math
.
cbrt
(
27
)
// 3
Math
.
cbrt
(
22
)
// ~2.8
Math.exp(x)
e
x
Equivalent to
Math.pow(Math.E, x)
Math
.
exp
(
1
)
// ~2.718
Math
.
exp
(
5.5
)
// ~244.7
Math.expm1(x)
e
x
− 1 Equivalent to
Math.exp(x) - 1
Math
.
expm1
(
1
)
// ~1.718
Math
.
expm1
(
5.5
)
// ~243.7
Math.hypot(x1, x2,...)
Square root of sum of arguments:
x1
2
+ x2
2
+ . . .
Math
.
hypot
(
3
,
4
)
// 5
Math
.
hypot
(
2
,
3
,
4
)
// ~5.36
232 | Chapter 16: Math
