Write the Complex Number in the Form a + Bi $$\left( \cos \frac { \pi } { 2 } + i \sin \frac { \pi } { 2 } \right)$$

Multiple Choice

Write the complex number in the form a + bi.
- $$\left( \cos \frac { \pi } { 2 } + i \sin \frac { \pi } { 2 } \right)$$

A) 7
B) $7 \mathrm { i }$
C) $- 7$
D) $- 7 i$