Small Basic Sample: Math.Sin, Math.Cos and Math.ArcTan
This article contains a sample program for Math.Sin(), Math.Cos() and Math.ArcTan() operations.
Subroutine Using Math.Sin() and Math.Cos()
Subroutine Math_PolarToCartesian() uses Math.Sin() and Math.Cos() operations to calculate Cartesian coordinate from polar coordinate.
Sub Math_PolarToCartesian
' Math | convert polar coordinate to Cartesian coordinate
' param r, a - polar Coordinate
' return x, y - Cartesian coordinate
_a = Math.GetRadians(a)
x = r * Math.Cos(_a)
y = r * Math.Sin(_a)
EndSub
Subroutine Using Math.ArcTan()
Subroutine Math_CartesianToPolar() uses Math.ArcTan() operation to calculate polar coordinate from Cartesian coordinate.
Sub Math_CartesianToPolar
' Math | convert Cartesian coordinate to polar coordinate
' param x, y - Cartesian coordinate
' return r, a - polar Coordinate (0<=a<360)
r = Math.SquareRoot(x * x + y * y)
If x = 0 And y > 0 Then
a = 90 ' [degree]
ElseIf x = 0 And y < 0 Then
a = -90
ElseIf x = 0 And y = 0 Then
a = 0
Else
a = Math.ArcTan(y / x) * 180 / Math.Pi
EndIf
' at this point -90<=a<=90
If x < 0 Then
a = a + 180
ElseIf x >= 0 And y < 0 Then
a = a + 360
EndIf
' at this point 0<=a<360
EndSub
Test Program
Program JXB040 is a test code for these subroutines above. The usage is just moving mouse on the program window. The top x, y are got by Mouse.X and Mouse.Y . The second r and a are calculated with Math_CartesianToPolar(). The last x and y are calculated with Math_PolarToCartesian().
