2020 ASRJC J2 MYCT Q5

Express \(2{{\mathrm{e}}^{\mathrm{i}\left( \frac{\pi }{4} \right)}}-2{{\mathrm{e}}^{\mathrm{i}\left( \frac{\pi }{3} \right)}}\) in the form \(r{{\mathrm{e}}^{\mathrm{i}\left( k\pi \right)}}\), where \(r\) is a positive real constant in exact trigonometric form and \(k\) is an exact constant such that \(-1 < k\le 1\).[3]