arccosine and operands greater than 1

Hi, I am using the arccosine function in a calculation. The operand I am giving the function is often greater than 1, but less than 2, so the results I get from arccosine are imaginary numbers. Can someone point me to an explanation of what the expected imaginary number should be?

Thanks,

Jason

Answer 1

[Kirby Fears]

In the Mathworks documentation for acos (), you can click the Inverse Cosine link. It provides the equation Matlab is using to create these imaginary results