# Solve function (and other code help)

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Liam Crocker on 7 Sep 2020
Edited: Liam Crocker on 7 Sep 2020
I wish to find what Z is at these heights, so I looked up the code for it S = solve(eqn,var)
Z = solve(Re.*Z/Re.+Z=.hi, Z)
hi = [0 , 11 , 20, 32 , 47, 51 , 71 , 84.852 , 90 ]
Re = 6356.766
However it returns me
>> solve(Re.*Z/Re.+Z==.hi)(Z)
solve(Re.*Z/Re.+Z==.hi)(Z)
Error: Invalid use of operator. (over the plus symbol)
Am I doing something wrong? I am a little confused this the code I looked up just says write solve, your equation = (something) (variable)
Other code help:
P2 = 101325 * exp(-B((h-h(1))/t(1)) - This was just a manual calculation I will use to see if I had written anything wrong.
ai = [-6.5000, 0, 1.0000, 2.8013, -0.0050, -2.8000, -2.0000,0]
B =(go/Rs)
go = 9.80666
Rs = .287054
B (returns value of 34.1631) %okay no problems here
But my full equation is (to edit this question further)

KSSV on 7 Sep 2020
Are you sure about the equation/ expression?
Re*Z/Re+Z==hi
Re gets cancelled...there is no point in the expression for Re. Z = hi/2; this what you get.
Liam Crocker on 7 Sep 2020
See thats what I was thinking, but is the piece of formula I have been given. It is meant to return values of I checked this on a calculator using the 4th Height value of 32 Liam Crocker on 7 Sep 2020 Samiu Haque on 7 Sep 2020
Edited: Walter Roberson on 7 Sep 2020
syms Z
hi = [0 , 11 , 20, 32 , 47, 51 , 71 , 84.852 , 90 ];
Re = 6356.766;
for i=1:length(hi)
A(i) = solve((Re*Z)/(Re+Z)==hi(i), Z);
fprintf('%0.4f\n', A(i))
end

Liam Crocker on 7 Sep 2020
So it needs a * to tell matlab I want it to times -B by (H-h(1))/Ti(1)
Edit: Accidentally clicked the trash when trying to see what OP was
Liam Crocker on 7 Sep 2020
Thank you! I sort of guessed the length part, just wasn't quite sure what the syms Z is, thanks to your explanation and reading the matlab explanation I understand that is is telling Matlab Z is a symbolic value of a unkown variable
Walter Roberson on 7 Sep 2020
Yes, you need to add multiplication.

R2020a

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