Excel VBA Lesson 7: Trigonometric Functions in Excel VBA

7.1 Understanding Trigonometric Functions

Excel VBA provides these key trigonometric functions:

• Sin - Returns the sine of an angle
• Cos - Returns the cosine of an angle
• Tan - Returns the tangent of an angle
• Atn - Returns the arctangent (inverse tangent) of a number

7.2 Angle Conversion in VBA

Since VBA uses radians, we convert degrees to radians using:

π radians = 180°
therefore
1° = π/180 radians

To get the precise value of π in VBA:

pi = 4 * Atn(1)  ' Most accurate way to get π

7.3 The Sin Function

The Sin function returns the sine of an angle in radians.

Syntax:

Sin(angle_in_radians)

Example 7.1: Calculating Sine of 90 Degrees

Private Sub CommandButton1_Click()
    Dim pi As Single 
    pi = 4 * Atn(1) 
    MsgBox "Sin(90°) is " & Round(Sin(pi/2), 4)
End Sub

Running the program produces this message:

7.4 The Cos Function

The Cos function returns the cosine of an angle in radians.

Syntax:

Cos(angle_in_radians)

Example 7.2: Calculating Cosine of 60 Degrees

Private Sub CommandButton1_Click()
    Dim pi As Single
    pi = 4 * Atn(1)
    MsgBox "Cos(60°) is " & Round(Cos(pi/3), 4)
End Sub

Running the program produces this message:

7.5 The Tan Function

The Tan function returns the tangent of an angle in radians.

Syntax:

Tan(angle_in_radians)

Example 7.3: Calculating Tangent of 45 Degrees

Private Sub CommandButton1_Click()
    Dim pi As Single
    pi = 4 * Atn(1)
    MsgBox "Tan(45°) is " & Round(Tan(pi/4), 4)
End Sub

Running the program produces this message:

Summary

✅ In This Lesson, You Learned:

These trigonometric functions are fundamental for engineering, physics, and geometry applications in Excel VBA.

🔗 Related Resources

• Excel VBA 365 Tutorial
• Excel VBA 2010 Tutorial
• Excel VBA Examples
• Visual Basic Tutorial