Root function help

[DanielleSavage]

Hello,

I tried to solve the darcy friction factor formula symbolically, but mathcad couldn't do it. So now I am trying to solve it using the root function. However, the answer that I get is the same as my guess all the time. What am I doing wrong? I have attached the worksheet. The root problem is at the very bottom.

Thanks

D

[MikeArmstrong]

I'm not sure your equations are correct.

Firstly, you define the function X(f) with a local definition and secondly you define X(f) again using the boolean equal operator.

Do you know the answer? Which equation is the root function meant to be applied to?

Mike

[DanielleSavage]

you are right I goofed. I got it to work.

D

[RichardJ]

You have X(f) defined as 1/sqrt(f), and then func(f) defined as X(f)-1/sqrt(f), so func(f) is zero for all values of f.

Your boolean version of the function X(f) below is not a fuction defintion, and has a unit mismatch.