## anonymous 5 years ago squrt(-a)*squrt(-b) is equal to squrt (-a)(-b) or not ?

1. anonymous

not it isn't. it is equal to -sqrt(-a)(-b)

2. anonymous

no it is equal to -1*squrt(a)(b)

3. anonymous

yes, that is the same as what I wrote. (-a)(-b)=(a)(b)

4. anonymous

i think we cant not multiply two numbers which are negative inside the sqrt...thats what the logic, i guess...what do u say ?

5. anonymous

you can do all the arithmetic functions within the square roots. sqrt(20) = sqrt((4)(5))

6. anonymous

sqrt(9) = sqrt(5+4)

7. anonymous

sqrt(9) is NOT equal to sqrt(4)+sqrt(5)

8. anonymous

what u told ll apply for positive numbers..not for negatives...otherwise the question what i posted would have a direct answer

9. anonymous

hey actually i saw this, when iam reading abt complex numbers

10. anonymous

yes, sqrt of a negative number is imaginary. so when you multiply an imaginary number with another imaginary number you get negative(their product) whereas if sqrt(-5)(-4) is given, it means you first multiply what is within the sqrt and THEN calculate the square root. It is kind of an extension of the BODMAS rule.

11. anonymous

if is so...then y sqrt(-a)*sqrt(-b) is not equal to sqrt(-a)(-b)....

12. anonymous

because you evaluate what is within the square root and then take its square root so sqrt(-a) X sqrt(-b) = i sqrt(a) X i sqrt(b) = i^2sqrt(ab)= -sqrt(ab)

13. anonymous

sqrt(number) is also a number. you must treat sqrt(number) as a number.

14. anonymous

sqrt(4) must be treated the same way you treat 2. so sqrt (4) X sqrt(4) means you are multiplying two separate numbers.

15. anonymous

you first evaluate the sqrt(4) and THEN do the multiplication. so sqrt(4) X sqrt(4) = 2 X 2 = 4.

16. anonymous

iam clear upto the part...that...sqrt(-a)*sqrt(-b) is equal to -1*sqrt(a)*sqrt(b)....am i right ?

17. anonymous

so sqrt(-a) X sqrt(-b) means you are taking the number sqrt(-a) and multiplying it by the number sqrt(-b). sqrt(-a) is the number i sqrt(a). sqrt(-b) is the number i sqrt(b). so when you multiply these two numbers you get i^2 sqrt(a)sqrt(b) = -1sqrt(ab)

18. anonymous

whereas when you are evaluating sqrt(-a X -b), you treat this as a number too, it is the number sqrt(-a X -b) = sqrt( ab)

19. anonymous

yes exactly ur right...i agree with u completely..infact thats what i was saying u right ?

20. anonymous

no, you were saying that you cannot perform multiplication within square roots, which you can.

21. anonymous

wait wait...

22. anonymous

if those two r individually correct, then y iam not able to write LHS=RHS, assuming LHS = sqrt(-a)*sqrt(-b), RHS=sqrt(-a)*(-b)....

23. anonymous

I think agian v cam to first...

24. anonymous

because LHS and RHS have two different meanings. LHS means you are taking the number sqrt(-a) and multiplying it with the number sqrt(-b) RHS means you are evaluating the number sqrt(-a X -b) which is the same as the number sqrt(ab)

25. anonymous

then what abt "-" sign...so u mean to say -sqrt(a*b) is equal to sqrt(-a*-b) ?

26. anonymous

sqrt (a) means square root of the number a. sqrt(-a) means the square root of the number -a. sqrt(-a X -b) means square root of the number (-a x -b) which is the same as square root of the number ab.

27. anonymous

hey i think i did typing mistake , while writing parentheses....but i understood ur concept....u r right...i conveyed u a wrong message without including brackets....hope so...but iam clear how "-" has come...

28. anonymous

so you have to first evaluate what number it is you are taking the square root of, and then square root it.

29. anonymous

r u a math student ?....where r u from ?

30. anonymous

31. anonymous

do it now and you will see what I am talking about.

32. anonymous

ok i ll do it..

33. anonymous

just copy and paste what I typed there into google and press enter. google has a built in calculator

34. anonymous

no, i'm not a math student. I am from India.

35. anonymous

36. anonymous

for ur 2 equations

37. anonymous

see what I meant? in the first case, the product of (-1 * -4) was done first and then the square root was applied to that number. (-1*-4) = 4. so sqrt(4) = 2 in the second case, sqrt(-1)*sqrt(-4), the square roots were evaluated first, which is i and 2i and THEN they were multiplied. which means i*2i = 2i^2 = -2.

38. anonymous

ya i got it..

39. anonymous

okay great. cheers!

40. anonymous

r u an engineering student ? ....math is ur favorite subject ?

41. anonymous

I am not a student. I finished graduation last year. Physics is my favorite subject. I just come here to help out sometimes.

42. anonymous

43. anonymous

ok ...i finished my under graduation in Mechanical engineerign from Hyderabad...presently working in a company, chennai....going to do my MS in Industrial Engineering in US...by this july end iam gonna fly...thats y iam just revising my basics before my classes ll start...Maths is hobby..

44. anonymous

oh okay. which university?

45. anonymous

JNTU,Kukatpally...do u know it ?

46. anonymous

oh yes. I know that university. One of my friend's sister studied there. but i meant which university are gonna do IE in US?

47. anonymous

okay...North Carolina State University (NCSU), Raleigh....do u know abt it ?

48. anonymous

Oh NCSU, I see. Good, that is a nice university. One of my friends graduated from there. Pack warm clothes. It is pretty cold in NC.

49. anonymous

ya its a good university....i love the ambiance there...it ll give u a blend of all the weathers....u can really enjoy...Btw...May-18th is my VISA ...bit nervous..

50. anonymous

oh, don't be nervous. It was easy for me. Just don't stammer and show nervousness when the guy asks you anything. takes 5 minutes max. where are going for VISA? chennai consulate?

51. anonymous

ya Chennai Consulate..

52. anonymous

actually, I just saw the temperatures. not so bad. 32 F is not that bad. It gets that cold here out in the west sometimes.

53. anonymous

okay, well all the best.

54. anonymous

from which university did u graduated ?

55. anonymous

USC

56. anonymous

ok so ur in Cali now ?

57. anonymous

yeah. I live in Orange County.

58. anonymous

ohh cool

59. anonymous

actually, I have to move to san francisco by next month.

60. anonymous

y so ?..r u working ?

61. anonymous

yes. As I said, I graduated last year.

62. anonymous

okkkk

63. anonymous

which branch r u ?...whats ur major ?

64. anonymous

I did computer engineering. did thesis on wireless networking.

65. anonymous

ok

66. anonymous

basically r u a telugu guy ?

67. anonymous

yes.

68. anonymous

ok

69. anonymous

But I haven't lived in Andhra for more than 2 years.

70. anonymous

ohhh...where u used to stay ? atleast do u know telugu r not ?

71. anonymous

I used to stay in rajamundry for less than 2 years. but I have lived most of my life in Dehradun and chennai, and now LA. and yes, we speak telugu at home.

72. anonymous

I speak telugu, tamil and hindi fluently.

73. anonymous

ur not sleeping by this time ?

74. anonymous

75. anonymous

I slept in the night for a bit. I can't sleep more, so I decided to stay up and go to office directly tomorrow.

76. anonymous

i was in HYD for 7 years...in Chennai for 1 year....i know telugu,tamil,english,hindi....little bit kanada

77. anonymous

oh good. that will come in handy here. everyone assumes you know hindi.

78. anonymous

alright, it was nice chatting with you. I'm gonna go make some food and have a couple of smokes. its a beautiful night here. All the best for your visa interview! Don't be nervous about it. I'm sure you will get it.

79. anonymous

hey really thanks...whats ur name ?...dont scold me as iam asking at last ...

80. anonymous

81. anonymous

thanks...

82. anonymous

bye now.

83. anonymous

hey bye bye...