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newatthis

  • 2 years ago

Multiply and simplify Radical Expression 1/2√5(1 1/2√20)

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  1. newatthis
    • 2 years ago
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    |dw:1370239174862:dw|

  2. newatthis
    • 2 years ago
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    Hi I got the answer of 7/2√5 but when I do it I get something different.

  3. yummydum
    • 2 years ago
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    okay so lets write that a little prettier to deal with:\[{{1\over2}\sqrt{5}}\times{1~{1\over2}\sqrt{20}}~~\implies~~{{1\over2}\sqrt{5}}\times{{3\over2}\sqrt{20}}~~\implies~~{\sqrt{5}\over2}\times{3\sqrt{20}\over2}\]now that that looks a little better, let's solve:\[{{\sqrt{5}\times3\sqrt{20}}\over2}={3\sqrt{100}\over2}\]because 5 x 20 = 100\[3(10)\over2\]i think you've got it from here :)

  4. yummydum
    • 2 years ago
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    oh i meant to write \[3(10)\over4\]sorry

  5. newatthis
    • 2 years ago
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    I'm a bit lost I have to simplify this so would'nt 1 1/2√20 be 2 3/2√5

  6. yummydum
    • 2 years ago
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    \[1 {1\over2} = {3\over2}\]\[\sqrt{20}= 2\sqrt{5}\]\[{3\over2}\times{2\over1}\sqrt{5}~~=~~{3\over\cancel{2}}\times{\cancel{2}\over1}\sqrt{5}~~=~~\large3\sqrt{5}\]

  7. newatthis
    • 2 years ago
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    but the answer comes out to \[\frac{ 7 }{ 2 }\sqrt{5}\]

  8. yummydum
    • 2 years ago
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    and where are you getting this from?

  9. newatthis
    • 2 years ago
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    Our teacher placed the answer as \[\frac{ 7 }{ 2 }\sqrt{5}\]

  10. newatthis
    • 2 years ago
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    I didn't get this answer either this is why it's confusing

  11. yummydum
    • 2 years ago
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    1/2 times 3/2 = 3/4 sqrt 5 times sqrt 20 = sqrt100 = 10 3/4 times 10 = 7.5 i dont know what your teacher was doing, maybe you copied the question wrong

  12. newatthis
    • 2 years ago
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    No it's printed on my paper

  13. yummydum
    • 2 years ago
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    then im really not sure

  14. newatthis
    • 2 years ago
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    I appreciate your help Thank you yummydum

  15. yummydum
    • 2 years ago
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    no problem :)

  16. newatthis
    • 2 years ago
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    I got as my final answer \[\frac{ 3 }{ 4 }\sqrt{5} \] this is why it was confusing

  17. newatthis
    • 2 years ago
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    I had a person help me don't I don't believe it's correct here is why unless I'm wrong

  18. saifoo.khan
    • 2 years ago
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    Alright so i read the whole problem. Where are you stuck? We should get 15/2.

  19. newatthis
    • 2 years ago
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    \[1\frac{ 1 }{ 2 }\sqrt{20}\] would be \[\frac{ 3 }{ 2 }\] and \[\sqrt{20} would be 2\] add both \[2\frac{ 3 }{ 2 }\sqrt{5}\]

  20. newatthis
    • 2 years ago
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    teacher has an answer of \[\frac{ 7 }{ 2 }\sqrt{5}\] could the teacher be wrong

  21. saifoo.khan
    • 2 years ago
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    Yes. Teacher added the sqrt5 by misatke. Or maybe the question you wrote is incorrect.

  22. newatthis
    • 2 years ago
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    question is multiply and simplify \[\frac{ 1 }{ 2 }\sqrt{5}\left( 1\frac{ 1 }{ 2 } \sqrt{20}\right)\]

  23. saifoo.khan
    • 2 years ago
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    |dw:1370243682678:dw|

  24. newatthis
    • 2 years ago
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    Why is this so complicated? I'm lost

  25. saifoo.khan
    • 2 years ago
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    Which step is it that you don't understand?

  26. newatthis
    • 2 years ago
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    how would I multiply \[\frac{ \sqrt{5} }{ 2 }\times \frac{ 3*2 }{ 2 }\sqrt{5}\] I thought you multiply numbers not square roots with numbers

  27. newatthis
    • 2 years ago
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    my answer was \[\frac{ 3 }{ 4 }\sqrt{5}\] maybe this is wrong

  28. saifoo.khan
    • 2 years ago
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    |dw:1370244388921:dw|

  29. newatthis
    • 2 years ago
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    Wouldn't we keep the root? and just multiply getting \[\frac{ 15 }{ 2 }\sqrt{5}\]

  30. saifoo.khan
    • 2 years ago
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    No ma'am. Whenever it's given: sqrt3 * sqrt3 we will get "3" as answer. The roots cancel out leaving you with ONE three.

  31. newatthis
    • 2 years ago
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    This is how I started \[\frac{ 1 }{ 2 }\sqrt{5}(1\frac{1 }{ 2 }\sqrt{20})\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{3 }{ 2 }\sqrt{5})\] \[\frac{ 1 }{ 2 }\times \frac{ 3 }{ 2 }=\frac{ 3 }{ 4 }\sqrt{5}\] I know this isn't corrected but I get this

  32. saifoo.khan
    • 2 years ago
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    How will you simplify sqrt 20?

  33. newatthis
    • 2 years ago
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    that's right it would be 4*5 which 4 goes down to 2 so it would be \[2\sqrt{5}\]

  34. saifoo.khan
    • 2 years ago
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    ^

  35. newatthis
    • 2 years ago
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    I forgot to add that \[\frac{ 1 }{ 2 }\sqrt{5}(2\frac{3 }{ 2 }\sqrt{5})\] it would be this correct and mix fractions to improper fractions would be \[2\frac{ 3 }{ 2 } would be \frac{ 7 }{ 2 }\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{ 7 }{ 2 }\sqrt{5})\]

  36. saifoo.khan
    • 2 years ago
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    You made a mistake again. :P It's not 2 3/2

  37. newatthis
    • 2 years ago
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    so it's \[\frac{ 2 }{ 1 }X\frac{ 3 }{ 2 }\]

  38. saifoo.khan
    • 2 years ago
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    No. I think you should redo the problem. Show me yor steps please.

  39. newatthis
    • 2 years ago
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    ok

  40. newatthis
    • 2 years ago
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    \[\frac{ 1 }{ 2 }\sqrt{5}(1\frac{ 1 }{ 2 }\sqrt{20})\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{ 3 }{ 2 } 2\sqrt{5})\] \[\frac{ 1 }{ 2 }\sqrt{5}(\frac{ 3 }{ 2 } 2\sqrt{5})\] at this point I'm lost

  41. saifoo.khan
    • 2 years ago
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    Awesome. No the 2's on right cancels out. Right?

  42. newatthis
    • 2 years ago
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    why would it cancel √20 would be 2√5 this is where I'm getting confused

  43. newatthis
    • 2 years ago
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    is 2 canceling with the other 2

  44. saifoo.khan
    • 2 years ago
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    sqrt(20) = sqrt(2*2*5) = 2 sqrt5 Agree?

  45. newatthis
    • 2 years ago
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    yes

  46. saifoo.khan
    • 2 years ago
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    Now the 2 from 2sqrt5 and the w in the denominator on the right canel out

  47. newatthis
    • 2 years ago
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    I'm with you on that

  48. saifoo.khan
    • 2 years ago
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    Right o what are we left with now?

  49. newatthis
    • 2 years ago
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    3√5

  50. saifoo.khan
    • 2 years ago
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    Right. And that is multiplied with..?

  51. newatthis
    • 2 years ago
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    \[\frac{ 1 }{ 2 }\sqrt{5}\]

  52. saifoo.khan
    • 2 years ago
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    Right now multiply it out.

  53. newatthis
    • 2 years ago
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    \[\frac{ 1 }{ 2 }\sqrt{5}\times \frac{ 3 }{ 1 }\sqrt{5}\] Is this looking correct?

  54. saifoo.khan
    • 2 years ago
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    yes

  55. newatthis
    • 2 years ago
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    \[\frac{ 3 }{ 2 }\sqrt{5}\]

  56. newatthis
    • 2 years ago
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    do I take of the √ and make it \[\frac{ 3 }{ 2 }\times \frac{ 5 }{ 1 }=\frac{ 15 }{ 2 }\]

  57. saifoo.khan
    • 2 years ago
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    Like a boss. (y)

  58. newatthis
    • 2 years ago
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    Thanks for everything wow :.)

  59. help123please.
    • 2 years ago
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    Good job helping @newatthis !!! @saifoo.khan

  60. help123please.
    • 2 years ago
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    Kudos to @yummydum too!

  61. saifoo.khan
    • 2 years ago
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    @yummydum is useless.

  62. help123please.
    • 2 years ago
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    No she isn't :p

  63. help123please.
    • 2 years ago
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    I'M useless.

  64. help123please.
    • 2 years ago
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    Yummydum isn't. Or you,for that matter.

  65. newatthis
    • 2 years ago
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    Thanks for everything it helps a lot when someone knows how to guide and explain it. :)

  66. saifoo.khan
    • 2 years ago
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    @help123please. believe me. I know her. @newatthis You're welcome. :)

  67. help123please.
    • 2 years ago
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    Well,yes...you've been here longer than me.

  68. saifoo.khan
    • 2 years ago
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    Lol. But no doubt she has a brown brain like me! D:

  69. help123please.
    • 2 years ago
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    O_O

  70. help123please.
    • 2 years ago
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    Yours is a great brain,Saif.

  71. help123please.
    • 2 years ago
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    U ARE 2 HELPFUL. Lol.

  72. saifoo.khan
    • 2 years ago
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    And it's brown too!

  73. help123please.
    • 2 years ago
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    Nope it's not.

  74. saifoo.khan
    • 2 years ago
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    I'm brown. Brain is brown too. Dummy is brown too. Hence she has a brown brain too.

  75. help123please.
    • 2 years ago
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    We're prolly weirding @newatthis out. Or at least,I am.

  76. help123please.
    • 2 years ago
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    :P

  77. help123please.
    • 2 years ago
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    'Hence,she has a brown brain too'. Hence. I like that word.

  78. saifoo.khan
    • 2 years ago
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    Lol.

  79. newatthis
    • 2 years ago
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    no I'm just doing math working my brain, or whatever is left. :)

  80. help123please.
    • 2 years ago
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    Saif,I just noticed your smartscore is mine,with the numbers flipped upside down. XD

  81. saifoo.khan
    • 2 years ago
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    Haha. Nice catch.

  82. help123please.
    • 2 years ago
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    IKR.

  83. help123please.
    • 2 years ago
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    *Flips PC upside down* OMGEE I HAVE A 99 SS!

  84. saifoo.khan
    • 2 years ago
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    Lol.

  85. help123please.
    • 2 years ago
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    98% of the time,when typing lol,you're not actually laughing. Did u know? :P

  86. saifoo.khan
    • 2 years ago
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    Make that 99%. I love laughing. It helps in exercising my face muscles. :P

  87. help123please.
    • 2 years ago
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    Lawl.

  88. saifoo.khan
    • 2 years ago
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    ;)

  89. newatthis
    • 2 years ago
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    so new question? \[2x \sqrt{7}(3x \sqrt{7})\] \[2x(3x)\sqrt{7}\sqrt{7}\] \[6x(\sqrt{49})\] Would this be correct?

  90. newatthis
    • 2 years ago
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    sorry I just threw this in here

  91. help123please.
    • 2 years ago
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    @newatthis please close this post and create a new thread.

  92. yummydum
    • 2 years ago
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    2x * 3x = 6x^2 not just 6x and √49 = 7 so now you have 6x^2 * 7 ....which is?

  93. newatthis
    • 2 years ago
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    \[42x ^{2}\]

  94. yummydum
    • 2 years ago
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    yes

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