Help solving for a variable

[agarrea]

I am new to Mathcad and having issues getting the program to solve for a variable. I was able to get my first equation to work, but when I tried plugging that value into the second equation I started having issues. The program would not let me plug in my value and solve for D. What am I doing wrong?

[Werner_E]

Not sure if I guessed correctly what you are looking for.

Would the use of a solve block or the root  command as shown in the picture help?

(You can't expect a solution if f1 is negative as with the first set of values you provided)

[ValeryOchkov]

The graphic solution/verification will bee good too

[agarrea · Accepted solution]

Thank you!

[agarrea]

I tried doing what you did and it is still not working for me

[Werner_E]

1) You have to use the Boolean (comparison) equal sign when you write an equation, not the evaluation equal sign as you did.

2) I changed back L from 0,56 m to the 56 m as in your first sheet as Mathcad can't find a solution with L=0,56m. Chances are that there is no solution with this combination of values.

Find attached the working file in Prime 5 format.

[agarrea]

Thank you so much. 

[LucMeekes]

Success!
Luc