pracma (version 1.9.9)

sind,cosd,tand, etc.: Trigonometric Functions in Degrees

Description

Trigonometric functions expecting input in degrees, not radians.

Usage

sind(x)
cosd(x)
tand(x)
cotd(x)
asind(x)
acosd(x)
atand(x)
acotd(x)
secd(x)
cscd(x)
asecd(x)
acscd(x)
atan2d(x1, x2)

Arguments

x, x1, x2

numeric or complex scalars or vectors

Value

Returns a scalar or vector of numeric values.

Details

The usual trigonometric functions with input values as scalar or vector in degrees. Note that tan(x) with fractional part does not return NaN as tanpi(x), but is computed as sind(x)/cosd(x).

For atan2d the inputs x1,x2 can be both degrees or radians, but don't mix! The result is in degrees, of course.

See Also

Other trigonometric functions in R.

Examples

# sind(x) and cosd(x) are accurate for x which are multiples
# of 90 and 180 degrees, while tand(x) is problematic.

x <- seq(0, 720, by = 90)
sind(x)                     # 0  1  0 -1  0  1  0 -1  0
cosd(x)                     # 1  0 -1  0  1  0 -1  0  1
tand(x)                     # 0  Inf  0  -Inf  0  Inf  0  -Inf  0
cotd(x)                     # Inf  0  -Inf  0  Inf  0  -Inf  0  Inf

x <- seq(5, 85, by = 20)
asind(sind(x))              # 5 25 45 65 85
asecd(sec(x))
tand(x)                     # 0.08748866  0.46630766  1.00000000  ...
atan2d(1, 1)                # 45

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