R sin() Function - Trigonometric Calculation

R provides a complete set of trigonometric functions: sin(), cos(), tan(), and their inverse functions.

These functions use radians by default and are frequently used in scientific computing and signal processing.

The syntax of trigonometric functions is as follows:

sin(x)
cos(x)
tan(x)
asin(x)   # 反正弦
acos(x)   # 反余弦
atan(x)   # 反正切

Parameter description:

xInput radian value (radians).

Example

# Trigonometric values of common angles
angle_deg <- c(0, 30, 45, 60, 90)

# Convert degrees to radians
angle_rad <- angle_deg * pi / 180

# Calculate sine value
print("sin value:")
print(round(sin(angle_rad), 4))

# Calculate cosine value
print("cos value:")
print(round(cos(angle_rad), 4))

# Calculate tangent value
print("tan value (note infinity at 90 degrees):")
print(round(tan(angle_rad), 4))

Executing the above code produces the following result:

[1] "sin 值:"
[1] 0.0000 0.5000 0.7071 0.8660 1.0000
[1] "cos 值:"
[1] 1.0000 0.8660 0.7071 0.5000 0.0000
[1] "tan 值（注意 90 度无穷大）:"
[1] 0.0000 0.5774 1.0000 1.7321      Inf

The arctangent function atan2() can be used to calculate the polar angle of a point (x, y) on a plane:

Example

# Calculate the polar angle of point (1,1) (should be 45 degrees)
angle_rad <- atan2(1, 1)
angle_deg <- angle_rad * 180 / pi
print(paste("Angle of point (1,1):", angle_deg, "degrees"))

# Calculate the polar angle of point (-1, 1) (should be 135 degrees)
angle_rad <- atan2(1, -1)
angle_deg <- angle_rad * 180 / pi
print(paste("Angle of point (-1,1):", angle_deg, "degrees"))

Executing the above code produces the following result:

[1] "点(1,1)的角度: 45 度"
[1] "点(-1,1)的角度: 135 度"

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