To express the complex number z = CosA + iSinA in the form I-Tan(kA), the discussion revolves around simplifying the expression 2/(1+z). The challenge lies in manipulating the expression using trigonometric identities and de Moivre's theorem. One suggested method involves multiplying by the conjugate (1-z) to simplify the denominator. The goal is to rewrite the result in the desired format, which may require further simplification. Ultimately, the solution hinges on correctly applying these mathematical principles.