doc: update mathutil package doc

docs/mathutil.md

@@ -36,6 +36,9 @@ import (
 -   [TruncRound](#TruncRound)
 -   [Range](#Range)
 -   [RangeWithStep](#RangeWithStep)
+-   [AngleToRadian](#AngleToRadian)
+-   [RadianToAngle](#RadianToAngle)
+-   [PointDistance](#PointDistance)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -556,3 +559,106 @@ func main() {
     // [1 2.1 3.2]
 }
 ```
+
+### <span id="AngleToRadian">AngleToRadian</span>
+
+<p>Converts angle value to radian value.</p>
+
+<b>Signature:</b>
+
+```go
+func AngleToRadian(angle float64) float64
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/mathutil"
+)
+
+func main() {
+    result1 := mathutil.AngleToRadian(45)
+    result2 := mathutil.AngleToRadian(90)
+    result3 := mathutil.AngleToRadian(180)
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+
+    // Output:
+    // 0.7853981633974483
+    // 1.5707963267948966
+    // 3.141592653589793
+}
+```
+
+
+### <span id="RadianToAngle">RadianToAngle</span>
+
+<p>Converts radian value to angle value.</p>
+
+<b>Signature:</b>
+
+```go
+func RadianToAngle(radian float64) float64
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/mathutil"
+)
+
+func main() {
+    result1 := mathutil.RadianToAngle(math.Pi)
+    result2 := mathutil.RadianToAngle(math.Pi / 2)
+    result3 := mathutil.RadianToAngle(math.Pi / 4)
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+
+    // Output:
+    // 180
+    // 90
+    // 45
+}
+```
+
+### <span id="PointDistance">PointDistance</span>
+
+<p>Caculates two points distance.</p>
+
+<b>Signature:</b>
+
+```go
+func PointDistance(x1, y1, x2, y2 float64) float64
+```
+
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/mathutil"
+)
+
+func main() {
+    result1 := mathutil.PointDistance(1, 1, 4, 5)
+
+    fmt.Println(result1)
+
+    // Output:
+    // 5
+}
+```

docs/mathutil_zh-CN.md

@@ -36,6 +36,9 @@ import (
 -   [TruncRound](#TruncRound)
 -   [Range](#Range)
 -   [RangeWithStep](#RangeWithStep)
+-   [AngleToRadian](#AngleToRadian)
+-   [RadianToAngle](#RadianToAngle)
+-   [PointDistance](#PointDistance)
 
 <div STYLE="page-break-after: always;"></div>
 
@@ -556,3 +559,105 @@ func main() {
     // [1 2.1 3.2]
 }
 ```
+
+### <span id="AngleToRadian">AngleToRadian</span>
+
+<p>将角度值转为弧度值</p>
+
+<b>函数签名:</b>
+
+```go
+func AngleToRadian(angle float64) float64
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/mathutil"
+)
+
+func main() {
+    result1 := mathutil.AngleToRadian(45)
+    result2 := mathutil.AngleToRadian(90)
+    result3 := mathutil.AngleToRadian(180)
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+
+    // Output:
+    // 0.7853981633974483
+    // 1.5707963267948966
+    // 3.141592653589793
+}
+```
+
+### <span id="RadianToAngle">RadianToAngle</span>
+
+<p>将弧度值转为角度值</p>
+
+<b>函数签名:</b>
+
+```go
+func RadianToAngle(radian float64) float64
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/mathutil"
+)
+
+func main() {
+    result1 := mathutil.RadianToAngle(math.Pi)
+    result2 := mathutil.RadianToAngle(math.Pi / 2)
+    result3 := mathutil.RadianToAngle(math.Pi / 4)
+
+    fmt.Println(result1)
+    fmt.Println(result2)
+    fmt.Println(result3)
+
+    // Output:
+    // 180
+    // 90
+    // 45
+}
+```
+
+### <span id="PointDistance">PointDistance</span>
+
+<p>计算两个坐标点的距离</p>
+
+<b>函数签名:</b>
+
+```go
+func PointDistance(x1, y1, x2, y2 float64) float64
+```
+
+<b>示例:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/mathutil"
+)
+
+func main() {
+    result1 := mathutil.PointDistance(1, 1, 4, 5)
+
+    fmt.Println(result1)
+
+    // Output:
+    // 5
+}
+```