found the answer myself.. note that there is a difference between sinx and sin(x)
function [sinx, error] = sinx_approx(x)
% approximates the value of sin(x), the approximation is more accurate as
% the number of terms selected is increased.
n= input('Up to how many terms would you like to evaluate?');
sinx=0;
for i=1:1:n
sinx=(-1)^(i+1) * x.^(2*i-1)/ factorial(2*i-1)+ sinx;
error=((sin(x)-sinx)/sin(x))*100;
display(sinx);
display(error);
end
end
%%Factorial is a built in command
solved Writing a function that calculates sine for inputted number of terms. MATLAB [closed]