SOLUTION: hi there i have a question about complex number my question is about Check the function differentiable : F(x)= |sin(x)| + i cos|y| thanks Apameh

That is a complex function of two variables x and y, so it
should be F(x,y) not F(x).

|sin(x)| is not differentiable at np

However since cos(-y) = cos(y), it is differentiable everywhere.

So F(x,y) = |sin(x)| + i*cos|y| is differentiable everywehere
except where x = np, where n is an integer.

Edwin