SOLUTION: what can we multiply to rationalize the denominator? {{{ (sqrt( 2 )xy^2)/(cube root of( 8 )xy^3) }}}

Algebra ->  Radicals -> SOLUTION: what can we multiply to rationalize the denominator? {{{ (sqrt( 2 )xy^2)/(cube root of( 8 )xy^3) }}}       Log On


   



Question 981108: what can we multiply to rationalize the denominator?
+%28sqrt%28+2+%29xy%5E2%29%2F%28cube+root+of%28+8+%29xy%5E3%29+

Found 2 solutions by Edwin McCravy, Alan3354:
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
+%28sqrt%28+2+%29xy%5E2%29%2F%28root%283%2C+8xy%5E3%29%29+

The cube root of 8 is 2 so we can take the 8 out of
the root and put 2 in front of the radical on the bottom.

The cube root of y3 is y so we can take the 3 out of
the root and put y in front of the radical on the bottom

+%28sqrt%28+2%5E%22%22+%29xy%5E2%29%2F%282y%2Aroot%283%2Cx%29%29+

The y in the bottom cancels into the y in the top.

+%28sqrt%28+2%5E%22%22+%29xy%29%2F%282root%283%2Cx%29%29+

To clear the cube root in the bottom multiply top and bottom by 
root%283%2Cx%5E2%29.  That will make the bottom become root%283%2Cx%5E3%29

+%28sqrt%28+2%5E%22%22+%29xy%29%2F%282root%283%2Cx%29%29+%22%22%2A%22%22+root%283%2Cx%5E2%29%2Froot%283%2Cx%5E2%29+

+%28sqrt%28+2%5E%22%22+%29xy%2Aroot%283%2Cx%5E2%29%29%2F%282root%283%2Cx%5E3%29%29+

+%28sqrt%28+2%5E%22%22+%29xy%2Aroot%283%2Cx%5E2%29%29%2F%282x%29+

Now the x's cancel:

+%28sqrt%28+2%5E%22%22+%29y%2Aroot%283%2Cx%5E2%29%29%2F2+

+%28y%2Asqrt%28+2%5E%22%22+%29root%283%2Cx%5E2%29%29%2F2+

You can either leave it like that or get all to one root:

 =  = 


++%28y%2Aroot%286%2C2%5E3%29+root%286%2Cx%5E4%29+%29%2F2%5E%22%22 = ++y%2Aroot%286%2C2%5E3%2Ax%5E4%29%2F2%5E%22%22 = ++y%2Aroot%286%2C8x%5E4%29%2F2%5E%22%22

Edwin

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
If you mean:
sqrt%282xy%5E2%29%2Froot%283%2C8xy%5E3%29
= y%2Asqrt%282x%29%2F%282y%2Aroot%283%2Cx%29%29
= sqrt%282x%29%2Aroot%283%2Cx%5E2%29%2F%282root%283%2Cx%29%2Aroot%283%2Cx%5E2%29%29
= sqrt%282x%29%2Aroot%283%2Cx%5E2%29%2F%282%2Aroot%283%2Cx%5E3%29%29
= sqrt%282x%29%2Aroot%283%2Cx%5E2%29%2F2x
==========================
= root%286%2C%282x%29%5E3%29%2Aroot%286%2C%28x%5E2%29%5E2%29%2F2x
= root%286%2C8x%5E7%29%2F2x
= x%2Aroot%286%2C8x%29%2F2x
= root%286%2C8x%29%2F2
======================
Your use of parentheses doesn't eliminate the ambiguities.