what is wrong with my matlab code

clc;

function approx = cosineApprox(x,t)

approx = 1

for i=1:1:t-1

nextTerms = (-1)^i*(x^(2*i))/factorial(2*i);

approx = approx + nextTerm;

end

end

x = 2*pi/3;

actual = cos(x);

disp("original value:");

disp(actual);

t = input("number of terms:");

approx = cosineApprox(x,t);

disp("approximate value:");

disp(approx);

-0.4996 >> approx = approxcosineFunction(x, 10) approX - -0.5000