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Mathematics 15 Online
OpenStudy (anonymous):

Please explain how to solve the following roots.

OpenStudy (anonymous):

\[\sqrt{27}\]

OpenStudy (anonymous):

That is equivalent to 3*sqrt3

OpenStudy (anonymous):

So how is the answer \[\sqrt[4]{2}\]

OpenStudy (anonymous):

That is the answer i got at least.

OpenStudy (anonymous):

idk how you got that

OpenStudy (anonymous):

\[\sqrt{27} = \sqrt{ 9 \times 3 } = \sqrt{ 9 } \times \sqrt{3} = 3\sqrt{3}\]

OpenStudy (anonymous):

Me neither.

OpenStudy (anonymous):

there is no root 2 in the prime factors of 27

OpenStudy (anonymous):

That's what I thought the answer would be. What about this one? Can you check my answer for it?

OpenStudy (anonymous):

\[\sqrt{32}\]

OpenStudy (anonymous):

ah, now that's 16*2 = 4 root(2)

OpenStudy (anonymous):

\[\sqrt{32}=\sqrt{16x2}=\sqrt{8x2x2}=\sqrt{4x2x2x2}=\sqrt{2x2x2x2}= 2\sqrt{4}\]

OpenStudy (anonymous):

tssss

OpenStudy (anonymous):

\[\sqrt{32} = \sqrt{ 16 \times 2 } = \sqrt{16} \times \sqrt{2} = 4 \sqrt{2}\]

OpenStudy (anonymous):

Oh. Well then how about this one. \[\sqrt{40}=\sqrt{4x10}=\sqrt{2x2x5x2}=5\sqrt{4}\]

OpenStudy (anonymous):

it's ok up to 4x10

OpenStudy (anonymous):

agfter that\[\sqrt{4} \times \sqrt{10} = 2 \sqrt{10}\]

OpenStudy (anonymous):

You are looking to break down a number into the product of a "good square" ( like 4,9,16,25,36 etc) and anohter number

OpenStudy (anonymous):

I am totally not understanding this.

OpenStudy (anonymous):

ok, hold on

OpenStudy (anonymous):

lets look at \[\sqrt{40}\]

OpenStudy (anonymous):

We want to break that 40 into 2 pieces

OpenStudy (anonymous):

one piece has to be a square the other doesnt matter

OpenStudy (anonymous):

You know what a square is?

OpenStudy (anonymous):

no

OpenStudy (anonymous):

ok, a square is a number multiplied by itsself.

OpenStudy (anonymous):

\[1^2 = 1 \times 1 = 1\]

OpenStudy (anonymous):

\[2^2 = 2 \times 2 = 4\]

OpenStudy (anonymous):

got it

OpenStudy (anonymous):

so the squares (up to 10 are) 1,4,9,16,25,36,49,64,81,100

OpenStudy (anonymous):

what you want to do with the number under the root sign is break it up into 2 parts, 1 square, the other not

OpenStudy (anonymous):

\[\sqrt{40}\]

OpenStudy (anonymous):

we have 40, that breaks down into 4 * 10

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

with 4 being the sqaure and 10 being not a square

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

you're always looking for the largest square to fit

OpenStudy (anonymous):

like with \[\sqrt{32}\]

OpenStudy (anonymous):

32 breaks down into 4x8 but also 16x2

OpenStudy (anonymous):

you want to choose 16x2

OpenStudy (anonymous):

after that, you can break up the root sign, and simply take the root of the square

OpenStudy (anonymous):

and voila, you're done

OpenStudy (anonymous):

\[\sqrt{40} = \sqrt{4 \times 10 } = \sqrt{4} \times \sqrt{10} = 2 \times \sqrt{10} = 2 \sqrt{10}\]

OpenStudy (anonymous):

the \[\sqrt{4} = 2\]

OpenStudy (anonymous):

ok so 40 would be 4*10=2*2*5*2= \[5\sqrt{2}\]

OpenStudy (anonymous):

nope, 40 = 4*10, you dont break in into any more pieces

OpenStudy (anonymous):

40 = 2 * 2 * 2 * 5 of course, but that doesnt really help

OpenStudy (anonymous):

So I am making this more complicated then this has to be?

OpenStudy (anonymous):

you need to break it into 2 pieces, 1 piece a nice square, the other just a number

OpenStudy (anonymous):

you're doing too much, yeah, and in the process you're confusing yourself

OpenStudy (anonymous):

Oh my gosh. I feel so stupid.

OpenStudy (anonymous):

another example, try \[\sqrt{50}\]

OpenStudy (anonymous):

nah, dont feel stupid for trying. People who don't try are stupid

OpenStudy (anonymous):

:) The answer is 10x5= \[10\sqrt{5}\]

OpenStudy (anonymous):

almost right

OpenStudy (anonymous):

it's 25*2 , can you give me the answer now?

OpenStudy (anonymous):

\[25\sqrt{2}\]

OpenStudy (anonymous):

\[\sqrt{50} = \sqrt{25*2} = \sqrt{25} \times \sqrt{2} = 5\sqrt{2}\]

OpenStudy (anonymous):

almost right again, you need to root the 25

OpenStudy (anonymous):

\[5\sqrt{2}\]

OpenStudy (anonymous):

yup that's the only trick you'll need for this kind of questions

OpenStudy (anonymous):

\[\sqrt{32}=16x2=16\sqrt{2}=8\sqrt{2}\]

OpenStudy (anonymous):

almost right

OpenStudy (anonymous):

\[\sqrt{32} = \sqrt{16 \times 2} = \sqrt{16} \times \sqrt{2} = 4 \sqrt{2}\]

OpenStudy (anonymous):

cause \[\sqrt{16} = 4\]

OpenStudy (anonymous):

not 8

OpenStudy (anonymous):

i gotto go eat now, kids are screaming they're hungry ;)

OpenStudy (anonymous):

I thought that was the answer. Thank you SO much for your help! I am going to try this on my own now. Bye! :D

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