# NumPy数学函数介绍和用法

## 本文概述

Numpy包含大量数学函数, 可用于执行各种数学运算。数学函数包括三角函数, 算术函数和用于处理复数的函数。让我们讨论一下数学函数。

## 三角函数

Numpy包含三角函数, 用于计算弧度中不同角度的正弦, 余弦和正切。

sin, cos和tan函数返回指定角度的三角比。考虑以下示例。

### 例子

``````import numpy as np
arr = np.array([0, 30, 60, 90, 120, 150, 180])
print("\nThe sin value of the angles", end = " ")
print(np.sin(arr * np.pi/180))
print("\nThe cosine value of the angles", end = " ")
print(np.cos(arr * np.pi/180))
print("\nThe tangent value of the angles", end = " ")
print(np.tan(arr * np.pi/180))``````

``````The sin value of the angles
[0.00000000e+00 5.00000000e-01 8.66025404e-01 1.00000000e+00
8.66025404e-01 5.00000000e-01 1.22464680e-16]

The cosine value of the angles
[ 1.00000000e+00  8.66025404e-01  5.00000000e-01  6.12323400e-17
-5.00000000e-01 -8.66025404e-01 -1.00000000e+00]

The tangent value of the angles [ 0.00000000e+00  5.77350269e-01  1.73205081e+00  1.63312394e+16
-1.73205081e+00 -5.77350269e-01 -1.22464680e-16]``````

numpy.degrees()函数可用于验证这些三角函数的结果。考虑以下示例。

### 例子

``````import numpy as np
arr = np.array([0, 30, 60, 90])
print("printing the sin values of different angles")

sinval = np.sin(arr*np.pi/180)

print(sinval)
print("printing the inverse of the sin")
cosec = np.arcsin(sinval)

print(cosec)

print("printing the values in degrees")
print(np.degrees(cosec))

print("\nprinting the cos values of different angles")
cosval = np.cos(arr*np.pi/180)

print(cosval)
print("printing the inverse of the cos")
sec = np.arccos(cosval)
print(sec)

print("\nprinting the values in degrees")
print(np.degrees(sec))

print("\nprinting the tan values of different angles")
tanval = np.tan(arr*np.pi/180)

print(tanval)
print("printing the inverse of the tan")
cot = np.arctan(tanval)
print(cot)

print("\nprinting the values in degrees")
print(np.degrees(cot))``````

``````printing the sin values of different angles
[0.        0.5       0.8660254 1.       ]
printing the inverse of the sin
[0.         0.52359878 1.04719755 1.57079633]
printing the values in degrees
[ 0. 30. 60. 90.]

printing the cos values of different angles
[1.00000000e+00 8.66025404e-01 5.00000000e-01 6.12323400e-17]
printing the inverse of the cos
[0.         0.52359878 1.04719755 1.57079633]

printing the values in degrees
[ 0. 30. 60. 90.]

printing the tan values of different angles
[0.00000000e+00 5.77350269e-01 1.73205081e+00 1.63312394e+16]
printing the inverse of the tan
[0.         0.52359878 1.04719755 1.57079633]

printing the values in degrees
[ 0. 30. 60. 90.]``````

## 舍入函数

numpy提供了各种功能, 可用于截断十进制浮点数的值, 将其舍入为十进制数的特定精度。让我们讨论舍入函数。

### numpy.around()函数

``numpy.around(num, decimals)``

SN Parameter Description
1 num 它是输入数字。
2 decimals 它是要舍入到的小数位数。默认值为0。如果此值为负, 则小数点将移到左侧。

### 例子

``````import numpy as np
arr = np.array([12.202, 90.23120, 123.020, 23.202])
print("printing the original array values:", end = " ")
print(arr)
print("Array values rounded off to 2 decimal position", np.around(arr, 2))
print("Array values rounded off to -1 decimal position", np.around(arr, -1))``````

``````printing the original array values: [ 12.202   90.2312 123.02    23.202 ]
Array values rounded off to 2 decimal position [ 12.2   90.23 123.02  23.2 ]
Array values rounded off to -2 decimal position [ 10.  90. 120.  20.]``````

### 例子

``````import numpy as np
arr = np.array([12.202, 90.23120, 123.020, 23.202])
print(np.floor(arr))``````

``[ 12.  90. 123.  23.]``

### 例子

``````import numpy as np
arr = np.array([12.202, 90.23120, 123.020, 23.202])
print(np.ceil(arr))``````

``[ 13.  91. 124.  24.]``

• 回顶