I'm trying to solve for beta but i keep getting the error " oblique(theta, beta, M_inf) Not enough input arguments. Error in beta (line 19) y = exp(betaln(z,w)). Please help

function f = oblique(theta,beta,M_inf)

theta = (2)*pi/180; % angle of attack in rads

M_inf = 1.5:0.1:4.5;

eqn = @(beta) ((2*cot (beta).*(M_inf.^2*sin(beta).^2) - 1)./(M_inf.^2.*(1.4 + cos(2*beta) + 2)))-tan (theta);

beta_guess = (pi/4); % angle in rads;

beta = fzero(eqn, beta_guess);

[Stephen23]

Your function cannot be used with FZERO. The FZERO documentation states that "fun accepts a scalar x and returns a scalar fun(x)." However your function returns a vector when called with a scalar:

theta = (2)*pi/180; % angle of attack in rads
M_inf = 1.5:0.1:4.5;
eqn = @(beta) ((2*cot(beta).*(M_inf.^2*sin(beta).^2) - 1)./(M_inf.^2.*(1.4 + cos(2*beta) + 2)))-tan (theta);
eqn(1.2)

ans = 1×31

0.0518 0.0721 0.0888 0.1028 0.1147 0.1249 0.1336 0.1412 0.1478 0.1536 0.1587 0.1632 0.1672 0.1709 0.1741 0.1770 0.1797 0.1821 0.1843 0.1863 0.1881 0.1898 0.1913 0.1928 0.1941 0.1953 0.1964 0.1975 0.1985 0.1994

[Dyuman Joshi]

Post your full code. As the error occurs in the 19th line and you have only posted 6 lines of the code.

[ms763]

How did you get it to return a vector for eqn(1.2)? Because I tried this and still get the same error

[ms763]

This is the full code

[Dyuman Joshi]

"This is the full code"

How do you run your code? How do you call the function oblique?