Quadratic Equation in VBA

Hi Experts,

I need some help to fix my Quadratic Equation in VBA. It looks fine except sqrt part.

Here is the normal equation below X =

-b +- √b^2-4(a)(c)
---------------------
2(a)


Here is my b value

b = (Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1)

Based on B my equation looks like this

X = - Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1) - Sqr(Range("C13") * Range("C14") / Range("C14") + vt) * (xf - 1) ^ 2 - 4 * ksp / 2


It would be great if someone can give an idea on sqrt part. Beside that all seems to be working.

Thanks,
Vik

Originally Posted by shg

This expression

Range("C13") * Range("C14") / Range("C14")

is always = C13, unless C14 = 0, in which case it blows up.

Can you please explain a bit. Also advise can I use sqrt function here as I am getting error using sqrt. I have limited knowldge of VBA so would be great help for right correction of code.

regards,
Vik

Based in this part of formula I am doing this as below.

√b^2-4(a)(c)

here b = (Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1)

My issue here is to get sqrt. If you can give me right code to use sqrt that would be great

so far this is the code I am using which I know it is wrong as I dont know how to use sqrt here in vba

X = - Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1) - Sqr(Range("C13") * Range("C14") / Range("C14") + vt) * (xf - 1) ^ 2 - 4 * ksp / 2

I seen that example earlier but I have doubt as it is sqr not sqrt , Just wondering where is calculating sqrt in this above example ? square root can be done using sqr as well ?

tried that option using that example and there I am getting error 5 "Invalid procedure call or argument (Error 5)"


result value was like -1.0000000000003e-02. I have defined all var as double , i tried to change as long but same error

ok, i will write condition in that case

like below , Any advise please ? here thecountXp is nothing but X only

thecountxp1 = -(Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1)) ^ 2 - 4 * ksp
thecountxp0 = -(Range("C13") * Range("C14") / Range("C14") + vt * (xf - 1))


If thecountxp0 And thecountxp1 >= 0 Then
thecountxp = (thecountxp0 + Sqr(thecountxp1)) / 2

ElseIf thecountxp0 And thecountxp1 < 0 Then

thecountxp = (thecountxp0 + Sqr(-thecountxp1)) / 2
End If