Answer:
The principal square root of -4 is 2i.
Step-by-step explanation:
= 2i
We have the following steps to get the answer:
Applying radical rule 
We get 
As per imaginary rule we know that 
= 
Now 
Hence, the answer is 2i.
<span>0.888 = 888 / 1000
hope that helps</span>