## Mathhelp346 2 years ago PLEASEE HELP PLEASE!!!: 1. (-1+i √5)^2 2. (2-3i √2)^2

1. TBMonkey

are they supposed to be equal?

2. Mathhelp346

No, they're two seperate problems

3. Mathhelp346

Sorry for the confusion

4. TBMonkey

no problem hang on a sec kk?

5. Mathhelp346

Ok, thanks

6. TBMonkey

the first one should be i*4.84 the second should be i*1.96

7. Mathhelp346

How did you figure those out?

8. Mathhelp346

I checked the answers at the back of my textbook and it says -4-2i√5. Is that the same thing?

9. TBMonkey

yes but more complicated(:

10. Mathhelp346

Oh, ok. But how did you get those answers anyways?

11. TBMonkey

step by step lol your book should tell you

12. Mathhelp346

It doesn't have an example on this type. I don't know how to solve it with a square root.

13. TBMonkey

What?

14. Mathhelp346

Can you show me how you solved it step by step?

15. anikay

I can!

16. Mathhelp346

Ok :o

17. anikay

18. Mathhelp346

xD Thank you

19. anikay

do you know what $i^2$ is?

20. Mathhelp346

yes -1

21. anikay

ok, so..... $(-1+i+\sqrt{5})^2$ that's it?

22. Mathhelp346

That's it?

23. anikay

is that the problem in your book?

24. Mathhelp346

$(-1+i \sqrt{5})^{2}$

25. Mathhelp346

It's that

26. anikay

ok thanks

27. anikay

so we square everything inside the parentheses. to get -4

28. anikay

because -1^2 = 1 and i^2 = -1 and sqrt(5)^2 = 5 right?

29. Mathhelp346

Yeah

30. anikay

so the answer should be -4.....imo

31. anikay

is there something about the problem I'm missing?

32. Mathhelp346

But the answers in my textbook say it's -4-2i√5. Or is your answer and the textbook's the same thing?

33. anikay

they aren't

34. anikay

mine is simplifying the expression..... is that what your book is asking for

35. Mathhelp346

The textbook says multiply

36. anikay

....omg I'm so sorry

37. anikay

*facepalm* I'm tired. gonna head to bed after I finish helping you

38. anikay

$(-1+i \sqrt{5})(-1+i \sqrt{5})$

39. anikay

foil

40. Mathhelp346

1+i√5^2?

41. anikay

ok, F.O.I.L. Front, Outside, Inside, Last

42. anikay

so first we multiply -1 by -1

43. anikay

ok we get 1 next we mutiply $-1*i \sqrt{5}$

44. anikay

then we do the same thing again for the inside terms

45. anikay

then the last, which is $i \sqrt{5}*i \sqrt{5}$

46. anikay

so all together, we get$1- i \sqrt{5} - i \sqrt{5} - 5$ which simplifies to $-4 -2i \sqrt{5}$

47. Mathhelp346

oh ok thank you

48. anikay

so F.O.I.L, gotta remember that :P

49. Mathhelp346

Ok ^-^ Good night

50. anikay

here's a picture, just for good measure |dw:1355203674722:dw|

51. anikay

night