MATLAB Answers

Solve function (and other code help)

1 view (last 30 days)
Liam Crocker
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)

  3 Comments

KSSV
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
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

Sign in to comment.

Accepted Answer

Samiu Haque
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
'Perhaps, this might help you'

  6 Comments

Show 3 older comments
Liam Crocker
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
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
Walter Roberson on 7 Sep 2020
Yes, you need to add multiplication.

Sign in to comment.

More Answers (0)

Products


Release

R2020a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!