Expression 6: "I" Subscript, "m" , Baseline equals negative cosine left parenthesis, StartFraction, cos left parenthesis, 2 theta Subscript, "z" , Baseline , right parenthesis Over "r" squared , EndFraction , right parenthesis hyperbolic sine left parenthesis, StartFraction, sin left parenthesis, 2 theta Subscript, "z" , Baseline , right parenthesis Over "r" squared , EndFraction , right parenthesisIm=−coscos2θzr2zsinhsin2θzr2z