Find the square root of \[ 16 i \] that graphs in the first quadrant. \[ [?]\left(\cos []^{\circ}+i \sin []^{\circ}\right) \]

Step 1 ：\( z = \sqrt{16i} \)

Step 2 ：\( 16i = 16e^{i(\frac{\pi}{2}+2k\pi)} \)

Step 3 ：\( z = \pm 4 e^{i(\frac{\pi}{4}+k\pi)} \)