Use Goal Seek or Solver ?

[Franklin]

How do I use Goal Seek or Solver or some mathematical
method in Excel to solve a problem like
3*tan(x)*(1/cos(x)- 4*(1/sin(x))*(1/tan(x).
This equation solves for the angle(x)with two intersecting
shafts, one 3 feet wide and the other 4, that meet at an
angle of 90 degrees (the problem can be expanded to
include other angles). The solved angle (x), in turn, can
provide for the longest ladder that can negotiate the
turn.

 

[Niek Otten]

You missed a few parens in your formula. I assumed them; please check
Let's say x is cell C1 and your formula

=3*TAN(C1)*(1/COS(C1))- 4*(1/SIN(C1))*(1/TAN(C1))

is in A1 and you want to solve x for your formula to result in zero.

Tools>Goals seek, Set cell = A1, To value is zero, By changing cell is C1.

You can get closer to zero by setting Tools>Options>Calculation and setting
Maximum change to more decimals.

--

Kind Regards,

Niek Otten

Microsoft MVP - Excel

 

[Bernard V Liengme]

Also if the values in C1 is an angel in degrees you will need to use
=3*TAN(radians(C1))*(1/COS(radians(C1)))-
4*(1/SIN(radians(C1)))*(1/TAN(radians(C1)))

Bernard