Excel's Goal Seek to Solve Nonlinear Problem

[fcharn]

I used Goal Seek in Excel to try to solve the problem
= 7*tan(x)*(1/cos(x)) - 9*(1/sin(pi - 123 - x))*(1/tan(pi -123 -x))
or
= 7*tan(x)*(1/cos(x)) - 9*(1/sin(.9984 - x))*(1/tan(.9984 - x))

I converted (pi - 123) or (180 - 123) = 57degrees or .9984 radians
in the equation, but x comes out meaningless to me using Goal Seek.
The problem solves for the angle (x) with two intersecting mine
shafts, one 7 feet wide and the other 9, that meet at an angle of 123
degrees.. The solved angle can provide for the longest ladder to
negotiate the turn.

 

[Niek Otten]

What were the parameters for the Goal seek? IOW, what cells did you use,
what were the formulas and values and what did you fill in in the Goal seek
dialog for the 3 items? And what were the settings of
Tools>Options>Calculation, Iteration, Maximum iterations and Maximum change?
What result did you get?

 

[Niek Otten]

In a private mail, I got this:

Niek,
Sorrow to impose on you again. Thanks for responding promptly to my
problem. I tried to email you by using the Excel user forum procedures, but
couldn't get access by giving my email address and password, so I am
approaching you directly.
In the Goal Seek menu, I placed the equation in cell A1, precisely as
shown in my forum message, used zero as the goal in the second box, and used
cell E1 in the third box. My settings were 100 iterations and a tolerance of
..0001.
My results were meaningless.
Thanks
Frank

1. What were the formulas? (certainly NOT = 7*tan(x)*(1/cos(x)) -
9*(1/sin(pi - 123 - x))*(1/tan(pi -123 -x)))
2. And the values???
3. What are "meaningless results"?

I'm getting tired of trying to answer questions where the poster keeps as
much as possible of the information to himself and leaves you to solve a
vaguely defined problem.

--
Still,

Kind regards,

Niek Otten

PS Do post again if you know what you're asking