MATLAB Answers

## Help on solving equation?

Asked by ABDULLA RAHIL

### ABDULLA RAHIL (view profile)

on 29 Apr 2019
Latest activity Answered by Stephan

### Stephan (view profile)

on 29 Apr 2019
Accepted Answer by Stephan

### Stephan (view profile)

Hello,
I need urgent help for the small code belwo to solave the equation I jave tried but I always seeing this error ((Error: Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters)).
Code is belwo:
A1=1.825*10^6;
Zi=67;
M=123;
B=50.29;
a=5;
Z=134;
AO0=2.6;
P0=54.6;
C=12;
Ka=2.45;
V=10^((-A1*(Zi^2)*sqrt(M))/(1+B*a*sqrt(M)));
syms A
eqn=AO0-(C*V*(A*(((1-Z*C^0.5)^(-1))+((AO0-P0)/(2*A))/(1+((AO0-P0)/(2*AO0))-(AO0/2)))*(Ka/AO0)-(A*(((1-Z*C^0.5)^(-1))+((AO0-P0)/(2*A))/(1+((AO0-P0)/(2*AO0)));
sola = solve(eqn, A)

KALYAN ACHARJYA

### KALYAN ACHARJYA (view profile)

on 29 Apr 2019
My suggestion break the eqn statement in multiple parts, because it is confusing check.

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R2018a

## 1 Answer

### Stephan (view profile)

Answer by Stephan

### Stephan (view profile)

on 29 Apr 2019
Accepted Answer

Hi,
try:
A1=1.825*10^6;
Zi=67;
M=123;
B=50.29;
a=5;
Z=134;
AO0=2.6;
P0=54.6;
C=12;
Ka=2.45;
V=10^((-A1*(Zi^2)*sqrt(M))/(1+B*a*sqrt(M)));
syms A
eqn=AO0-C*V*A*(((1-Z*C^0.5)^(-1))+((AO0-P0)/(2*A))/(1+((AO0-P0)/(2*AO0))-(AO0/2)))*(Ka/AO0)-(A*(((1-Z*C^0.5)^(-1))+((AO0-P0)/(2*A))/(1+((AO0-P0)/(2*AO0)))));
sola = double(solve(eqn, A))
result is:
sola =
133.8103
Does this appear to be a correct result? If not check the parenthesis of your equation.
Best regards
Stephan

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