1 - 1^2.5 == 0 % Let's ignore the rounding errors...
This is correct. But you calculate something else:
x = -1;
1 + x^2.5
This is:
1 + (-1)^2.5
which is 1 + 1i. The parentheses matter. Or if you store the -1 in a variable, the code is equivalent to:
1 + (x)^2.5
"How can i tell matlab that no Complex Calculus is needed?"
You can't. The result of 1+(x)^2.5 with a negative x is complex and you cannot convert this to 0 - except with catching these values explicitly:
y = zeros(N, 1);
for n = 1:N
if x(n) >= 0
y(n) = 1 + x(n)^2.5;
end
end
