I've been using this for a Newton Approximation in Matlab function x = Newton(f, fp, x, nmax, e) % f is an inline function which we apply Newton's method on % fp is an inline function that is the derivative of function f % x is the initial guess of the root % nmax is the total number of iterations done % e is the error used to control convergence fprintf('x(0) = %10g \n', x) for n = 1:nmax d = f(x)/fp(x); x = x - d; fprintf('x(%i) = %10g \n', n, x) if abs(d) < e fprintf('Converged! \n') return end end with this to run it: %declare our function f f = inline('e^x+2^(-1*x)+2*cos(x)-6'); % declare the derivative of function f fp = inline('e^x-ln(2)*2^(-1*x)-2*sin(x)'); % declare total number of iterations to be undertaken nmax = 100; % declare value of initial starting point x = 1.0; % declare amount of error allowed e = 10.0e-5; % carry out iteration using function above x = newton2(f,fp,x,nmax,e); This isn't working or running for this function, but has run fine for every other function. I'm not sure what isn't working about it. I keep getting the error: Error using inline/subsref (line 13) Not enough inputs to inline function. Error in newton2 (line 11) d = f(x)/fp(x); But I am very new to Matlab, and have no idea what this means.