# Thread: Need a little Help

1. ## Need a little Help

Can someone explain to me how to solve these questions. And what they mean by find the principal square root or how its different then finding a regular square root. All help is appreciated. Thanx

2. Why don't you tell us what you think the answer to each of this is.
As it is, it appears as if you are asking us to take a test for you.

3. If you would read underneath it i asked for an explanation plato, you would see i asked if someone could EXPLAIN to me these type of problems and what made the principal of the equation different then the others, you must have skipped that part (and this is not even the whole test). Anyways thanx qbkr, but could you provide an explanation to the steps of solving?

4. Originally Posted by Soldja Soul3ss
If you would read underneath it i asked for an explanation plato, you would see i asked if someone could EXPLAIN to me these type of problems and what made the principal of the equation different then the others, you must have skipped that part (and this is not even the whole test). Anyways thanx qbkr, but could you provide an explanation to the steps of solving?
do you know how to go from radicals to powers? if so, this will be a lot easier to understand.

the rules we use are as follows.

let "xroot" represent any root.
in general, by the laws of surds (and exponents):

xroot(a*b) = xroot(x)*xroot(b)

so we can find the product of numbers under the root, and then split them into the roots of the products. usually you do this in such a way, that most of the roots end up as "nice numbers"

e.g. the first question:
sqrt(8a^2) = sqrt(2*4*a^2) = sqrt(2)*sqrt(4)*sqrt(a^2) = sqrt(2)*2a

also, these posts may help:

http://www.mathhelpforum.com/math-he...some-help.html

http://www.mathhelpforum.com/math-he...tial-form.html

http://www.mathhelpforum.com/math-he...root-help.html

there are a lot more around, but i can't find them at the moment and i also don't have much time to explain your problems to you. i'm leaving very soon

5. What do you mean by "nice numbers" exactly?

6. Originally Posted by Soldja Soul3ss
What do you mean by "nice numbers" exactly?
here i say "nice numbers" to mean that their roots are whole rational numbers that we know the various roots of.

sqrt(4) is nice since it equals 2 a whole rational number.
sqrt(64) is nice since it is 8
sqrt(36) is nice since it is 6

so for instance:

sqrt(72) that's not nice. but i can change this into sqrt(2*36) = sqrt(2)*sqrt(36)
now sqrt(36) is "nice", so i end up with 6*sqrt(2)

7. ## Re:

3.C
4. D (i believe)
7. C
8.A
9.B

I do not have time right know to type out the work, as I am grading 1,000 plus comics right now!

-qbkr21

8. Ahhh that makes sense lol, thanx dude. I'll try to do them now, thanx for the help before leaving, appreciate it bro.

9. Thanx qbkr, im gonna try to do them on my own though first (yes for once :P) and let you guys see my answers and you can tell me if i screwed up somewhere.

10. Originally Posted by qbkr21
3.C
4. D (i believe)
7. C
8.A
9.B
yes, you are right, 4 is D

sqrt(x^2*y) = sqrt(x^2)*sqrt(y) = xsqrt(y)

11. Originally Posted by Soldja Soul3ss
Thanx qbkr, im gonna try to do them on my own though first (yes for once :P) and let you guys see my answers and you can tell me if i screwed up somewhere.
so, qbkr21 gave you the answers, now figure out how he got there. (i didn't check his answers but i'm sure they are correct!)

12. Okay i learned part of it from what you said, but how do i get rid of exponents in teh square root? It just cancls itself out or i take it away....or somethin?

13. Originally Posted by Soldja Soul3ss
Okay i learned part of it from what you said, but how do i get rid of exponents in teh square root? It just cancls itself out or i take it away....or somethin?
see http://www.mathhelpforum.com/math-he...tial-form.html

i explain there (in very basic terms) how to go from radicals to exponents.

basically for the sqrt, it is the same as saying to the 1/2 power. and when we raise a number to a power, we multiply the power of the number by the power we are raising it to, and that becomes the new power

so, for example, sqrt(x^2) = (x^2)^(1/2) = x^(1/2 * 2) = x^1 = x

and sqrt(x^3) = (x^3)^(1/2) = x^(3 * 1/2) = x^(3/2)

14. Ahh okay thats good examples, much simpler now hehe.

15. Okay im trying as we speak :P. Cya when your back.

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