මේ ගාණ හදමු

elaelkiri

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Jun 8, 2018
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A හොයන්ඩ
 

sandun36

Well-known member
  • Jan 28, 2009
    1,731
    440
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    r is common
    Compare right with left side.
    If 729 can be written as X^(1/3)
    left side of equation = X^(1/3 *3r) = X^r
    Hence X=A
    Therefore;
    X^(1/3) = 729
    X = 9 = A
     

    imhotep

    Well-known member
  • Mar 29, 2017
    14,855
    8
    35,441
    113
    r is common
    Compare right with left side.
    If 729 can be written as X^(1/3)
    left side of equation = X^(1/3 *3r) = X^r
    Hence X=A
    Therefore;
    X^(1/3) = 729
    X = 9 = A

    Till the last step the logic is correct.. Fine, but
    If x^(1/3) = 729... i.e the cube root of x = 729 (NOT the cube of x or x^3)
    then x= 729^3 = 387420489
     

    jamiezue

    Well-known member
  • Jul 28, 2008
    12,014
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    8,856
    113
    -~උලක් උඩ-~
    729 ^3r =A^r

    729^3r ={cube root(A)}^3r
    since the numbers are equal with exponents and exponents are the same, numbers should be equal
    then,
    729= cuberoot of A
    A =387420489????:confused::sorry:
     

    imhotep

    Well-known member
  • Mar 29, 2017
    14,855
    8
    35,441
    113
    729 ^3r =A^r

    729^3r ={cube root(A)}^3r
    since the numbers are equal with exponents and exponents are the same, numbers should be equal
    then,
    729= cuberoot of A
    A =387420489????:confused::sorry:

    Yes.. what's confusing?
    729 = cuberoot of A
    Then A= cube of 729 which is 387420489 ;)

    If you all still don't get it let r=1..
    Then 729^3 = A
    Pretty obvious.. isn't it?
     
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