Find all complex numbers z such that z^4=-4 Note: All solutions should be expressed in the form a + bi, where A and B are real numbers.
z^4 = (z^2)^2
z^2 = pm sqrt(-4)
z^2 = +- 2i
z = sqrt(2i) or sqrt(-2i) or -sqrt(2i) or -sqrt(-2i)
I trust you can express it in a + bi. gl
+78 
