Please help me with this little algebra problem

  • Thread starter roger12
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  • #1
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Homework Statement



Simplify the following, giving the result without fractional indices:

[(x^2 -1)^2 * √(x+1)]/ (x-1)^3/2

Homework Equations


The Attempt at a Solution



There are no common bases to add the indices and no common indices to multiply out the bases so I tried this and got it wrong, please show me where though:

[(x-1) (x+1)]^2 * (x+1)^(1/2)] / (x-1)^(3/2)

=[(x-1)^2 * (x+1)^2 * (x+1)^(1/2)] / (x-1)^(3/2)

multiplied the indices by 2 and got rid of the fractions

=[(x-1)^4 * (x+1)^4 * (x+1)] / (x-1)^3

= (x-1) *(x+1)^5

But my textbook says it is :( x + 1 )^2 √( x^2 - 1 )

Thank You.
 

Answers and Replies

  • #2
lewando
Homework Helper
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multiplied the indices by 2 and got rid of the fractions

=[(x-1)^4 * (x+1)^4 * (x+1)] / (x-1)^3

= (x-1) *(x+1)^5

You effectively squared the original problem. Now you need to un-square your result.
 
  • #3
HallsofIvy
Science Advisor
Homework Helper
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"Without fractional indices" just mean you need to use the square root:
[tex](x- 1)^{3/2}= \sqrt{(x-1)^3}[/tex]
 
  • #4
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Thank You, Everyone.
 

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