Look at these expressions:
Even if every function and variable is real, the result is a complex number. Each step seems valid, but the sequence gives unexpected results. It seems to arise from the particular way it expresses the denominator of cos(atan2(y,x)).
Is the result valid? If not, how can I avoid this transformation?
sqrt(x^2 + y^2) = abs(x + i*y)
All this appears inside a symbolic expression (x and y are expressions too), so I can't manually rewrite them.