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 2nd July 2007, 04:09 PM #1 becomingagodo Banned   Join Date: Mar 2007 Posts: 698 Exponents and roots help Well, I reading through the Chapter 5 in Algebra demystified I came across this 6x^2 x^(1/2)= You're mean't to rewrite it so it is simpler. The anwser came out as 6x^5/2 Can someone explain this. 3/2 ^(1/2)= 6^(1/2)/2 Can someone also explain this. 16x^8^(1/4)= 2x^2 Seriously this must be wrong, how the hell does that equal 2x^2. Before I end up stabbing myself out off anger, someone please help me. Sorry, I don't know how to express square roots or roots, so I had to do the power trick. I anwsered about 15/18 correct, however these three problems got me.
 2nd July 2007, 04:36 PM #3 Jekyll Graduate Poster     Join Date: Apr 2005 Location: The other other place Posts: 1,589 Ok, so: (6x^2)*( x^(1/2))= 6*(x^4/2)*( x^(1/2)) and we can add exponents when we multiply two expressions with the same bottom (x). so: (6x^2)*( x^(1/2))=6* (x^ ((4+1)/2)) Now, the next one is different. The rule is: (a^b)^c = a^(b*c) for all a, b and c. Can you work it out from this? And relax, maths is meant to be more fun than this, don't take it so seriously. __________________ And I looked. And behold a green horse, and his name that sat on him was death. ~Tyndale New Testament
 2nd July 2007, 04:44 PM #4 andyandy anthropomorphic ape     Join Date: Apr 2006 Location: up a tree Posts: 8,213 Originally Posted by becomingagodo Well, I reading through the Chapter 5 in Algebra demystified I came across this 6x^2 x^(1/2)= You're mean't to rewrite it so it is simpler. The anwser came out as 6x^5/2 Can someone explain this. 3/2 ^(1/2)= 6^(1/2)/2 Can someone also explain this. 16x^8^(1/4)= 2x^2 Seriously this must be wrong, how the hell does that equal 2x^2. Before I end up stabbing myself out off anger, someone please help me. Sorry, I don't know how to express square roots or roots, so I had to do the power trick. I anwsered about 15/18 correct, however these three problems got me. the first one $6x^2.x^{0.5}$ just requires that you remember $x^n.x^m = x^{n+m}$ so $6x^2.x^{0.5} = 6x^{2+0.5} = 6x^{2.5} = 6x^{5/2}$ The second one requires that you know $(\frac{a}{b})^n = \frac{a^n}{b^n}$ but is also a bit tricky.... first you need to write the fraction in a different form $\frac{3}{2} = \frac{(3)(2)}{(2)(2)}$ all you've done here is multiply both top and bottom by 2 - so the fraction is still the same - 3/2 = 6/4. now you can apply the formula; $(\frac{3}{2})^{0.5} = \frac{((3)(2))^{0.5}}{((2)(2))^{0.5}} = \frac{6^{0.5}}{2}$ The last one requires that you know $(ax)^n = a^n.x^n$ so first write your equation as $(16x^8)^{0.25} = (16)^{0.25}.(x^8)^{0.25} = 2.x^{8(0.25)} = 2x^2$ hope that helps.... i see that half of JREF has already answered in the time it took to type that in latex....oh well.... __________________ "Contentment is found in the music of Bach, the books of Tolstoy and the equations of Dirac, not at the wheel of a BMW or the aisles of Harvey Nicks." Last edited by andyandy; 2nd July 2007 at 04:54 PM.
 2nd July 2007, 04:46 PM #5 becomingagodo Banned   Join Date: Mar 2007 Posts: 698 Thank you, I understand it now. 2.5 how do you turn this into a improper fraction? I forgot the rule again. Last edited by becomingagodo; 2nd July 2007 at 05:00 PM.
 2nd July 2007, 05:36 PM #6 andyandy anthropomorphic ape     Join Date: Apr 2006 Location: up a tree Posts: 8,213 Originally Posted by becomingagodo Thank you, I understand it now. 2.5 how do you turn this into a improper fraction? I forgot the rule again. all you need to do is get 2.5 to being an integer (1,2,3 etc), so in this case all you need to do is multiply by 2.... $2.5 = \frac{(2.5)(2)}{2} = \frac{5}{2}$ More generally if you have any number with 1 decimal place, you can convert it to a fraction by multiplying by 10.... $2.5 = \frac{(2.5)(10)}{10} = \frac{25}{10}$ Once you have this, if the numerator and denominator have a common factor, you can simplify. In this case both 25 and 10 can be divided by 5, so $\frac{25}{10} = \frac{5}{2}$ __________________ "Contentment is found in the music of Bach, the books of Tolstoy and the equations of Dirac, not at the wheel of a BMW or the aisles of Harvey Nicks."

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