## anonymous 3 years ago Simplify the number using the imaginary unit i: (square root) -28 options: a. 2(square root) -7 b. -2(square root) -7 c. i(square root) 28 d. 2i(square root) 28

1. anonymous

Ok so it is $\large{\sqrt{-28}}$ Correct?

2. anonymous

Factor 28 first to find the perfect square. and remember that i=√(-1)

3. anonymous

Yes. @SheldonEinstein

4. anonymous

$\large{\sqrt{-28} = \sqrt{-1}\sqrt{28} = \sqrt{-1} \sqrt{4*7}}$

5. anonymous

So it will be $\large{(\sqrt{-1}) 2\sqrt{7} }$

6. anonymous

Now as we know that $\large{\sqrt{-1} = i (\textbf{IOTA})}$

7. anonymous

So we have answer : $$\large{ i \sqrt{28} }$$

8. anonymous

Got it?

9. anonymous

Yes thanks for both of your help and Sheldon for explaining so well :)

10. anonymous

You're welcome and thanks for the appreciation.

11. anonymous

i√28 is not fully simplified.

12. anonymous

Options have isqrt{28}

13. anonymous

Hence no need to simplify further.

14. anonymous

Ah, yes. After a second look 2i√7 isn't an option.

15. anonymous

Yeah, at first I thought the same and hence simplified it further but when saw the options again , I got to see the option i sqrt{28}...