VBA Function (Something wrong with my equation?)

[BalbasNiBarabas]

Hello guys!

Would just like some verification on why am I getting the wrong value/answer to this.

Here's the problem:

If d <= R then:
tank = pi * d ^ 2 / 3 * (3 * R - d)

but if d<=h - r then:
tank = 2 / 3 * pi * R ^ 3 + pi * R ^ 2 * (d - H)

Else:
tank = 4 / 3 * pi * R ^ 3 + pi * R ^ 2 * (H - 2 * R) - pi * (H - R) ^ 2 / 3 * (3 * R - H + d)

Below is my vba code:

Function tank(R As Double, H As Double, d As Double) As Double
Dim pi As Double
pi = WorksheetFunction.pi()
If d <= R Then
    tank = pi * d ^ 2 / 3 * (3 * R - d)
ElseIf d <= H - R Then
    tank = 2 / 3 * pi * R ^ 3 + pi * R ^ 2 * (d - H)
Else
    tank = 4 / 3 * pi * R ^ 3 + pi * R ^ 2 * (H - 2 * R) - pi * (H - R) ^ 2 / 3 * (3 * R - H + d)
End If
End Function

Let me know your thoughts.

Thank you!

 

[jasonb75]

Would just like some verification on why am I getting the wrong value/answer to this.

Sample values for R, H and D with actual and expected results?

 

[Leandroarb]

Sorry if I am completely wrong, because I am not very keen on calculations.
Did you look at the hierarchy of operations to separate them correctly with parentheses?

 

[rlv01]

Based on your posted graphic, your 2nd eqn

tank = 2 / 3 * pi * R ^ 3 + pi * R ^ 2 * (d - H)

is using H where it should be using R.

 

[BalbasNiBarabas]

@rlv01 thank you for pointing out! Got it!

The code is working perfectly.

I am just a beginner in VBA and actually practicing.

Thank you guys for you help! @Leandroarb @jasonb75