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Mathematics 19 Online
OpenStudy (brooke..help00):

@phi @mathmale @welshfella Question in comments:)

OpenStudy (dallascowboys88):

...??

OpenStudy (brooke..help00):

A rectangle has a length of \[\sqrt[5]{16} =\]Heighth and a width of \[2_{5}^{1}\] Find the area of the rectangle.

OpenStudy (brooke..help00):

The first exponent is length not height :/

OpenStudy (mrnood):

is that \[2\frac{ 1 }{ 5 } or 2^{\frac{ 1 }{ 5}}\]

OpenStudy (mrnood):

how can you write "5th root" using exponents?

OpenStudy (brooke..help00):

\[2^{\frac{ 1 }{5 }}\]

OpenStudy (mrnood):

OK - makes sense - so how can you write "5th root" using exponents?

OpenStudy (brooke..help00):

\[16^{5}?\]

OpenStudy (mrnood):

it's \[16^{\frac{ 1 }{ 5 }}\] so write the expression for the area, using the lenght and width in exponent form

OpenStudy (brooke..help00):

\[16^{\frac{ 1 }{5? }} + 2 ^{\frac{ 1 }{ 5 }} ?\]

OpenStudy (brooke..help00):

That doesn't seem right..:/

OpenStudy (mrnood):

well area = width TIMES length you have written PLUS so now look and see that \[a^{x} \times b ^{x} = (ab)^{x}\] So simplify your expression like that

OpenStudy (brooke..help00):

Would it be \[2^{\frac{ 4 }{ 5 }}\]

OpenStudy (brooke..help00):

Because the square root of 16 is 4. There was 5 as an exponent so... \[\frac{ 4 }{ 5 } \times \frac{ 1 }{ 5 } = 2 \frac{ 4 }{ 5 }\]

OpenStudy (mrnood):

your answer should have been \[16^{\frac{ 1 }{ 5 }}\times 2^{\frac{ 1 }{ 5 }}\] So simplify that using the method I gave above

OpenStudy (brooke..help00):

Oh ok:)

OpenStudy (brooke..help00):

Wait I'm really confused now.

OpenStudy (mrnood):

don't panic slow down and go back and read what we said then use my example to simplify your equation

OpenStudy (mrnood):

Let's review: We know that length = 5th root (16) And the is the same as \[16^{\frac{ 1 }{ 5 }}\] And we know tha the width is \[2^{\frac{ 1 }{ 5}}\] And we know area= lenght xwidth or \[A = 16^{\frac{ 1 }{ 5}} \times 2^{\frac{ 1 }{ 5 }}\] OK?

OpenStudy (brooke..help00):

I am so sorry! My computer died !

OpenStudy (mrnood):

so do you see what we did above...?

OpenStudy (brooke..help00):

Yes, so I would multiply them. Would I turn them improper then?

OpenStudy (brooke..help00):

@MrNood

OpenStudy (brooke..help00):

?

OpenStudy (michaelbp):

a=3440 ?

OpenStudy (brooke..help00):

Well seeing that my answer choices only start with two I suggest your wrong, but thans for the other 3338. Maybe you could turn that into people helping me?

OpenStudy (phi):

the trick in this one is knowing 16 is 2^4 so do \[ (2^4)^\frac{1}{5} \cdot 2^\frac{1}{5} \]

OpenStudy (phi):

now you use rules about exponents (2^4)^(1/5) can be written as 2^(4/5) (by multiplying 4*1/5 to get a "new" exponent)

OpenStudy (brooke..help00):

Do I need to turn them improper?

OpenStudy (phi):

no. once you have the same base (2 in this case) you add the exponents (when multiplying) easy example: \( 2^1 \cdot 2^2 = 2^3 \) in this problem: \(2^\frac{4}{5} \cdot 2^\frac{1}{5} = \)?

OpenStudy (phi):

you can add the exponents, so add 4/5 plus 1/5 the fractions have the same denominator so you add the tops (numerators) and keep the denominator as 5

OpenStudy (phi):

lost ?

OpenStudy (brooke..help00):

Would it be 2 square?

OpenStudy (phi):

do you know how to add 4/5 + 1/5 ?

OpenStudy (phi):

it would be cheating (a bit) but, you could use a calculator to add 4/5 + 1/5 what do you get ?

OpenStudy (brooke..help00):

4/5 + 1/5 = 1 I know that. Its just all of my answer choices start with 2.

OpenStudy (phi):

yes, so what we are doing is width times height: \[ \sqrt[5]{16} \cdot 2^\frac{1}{5} \] we changed the "root" to the equivalent "exponent" form: \[ \sqrt[5]{16} = 16^\frac{1}{5} \] \[ 16^\frac{1}{5} \cdot 2^\frac{1}{5} \] we then changed 16 to \(2^4\) (2*2*2*2 is 16) \[ (2^4)^\frac{1}{5} \cdot 2^\frac{1}{5} \] we then use the rule to simplify the first part: \[ 2^\frac{4}{5} \cdot 2^\frac{1}{5} \] now we know if we multiply the same base (2 here) we add the exponents \[ 2^\frac{4}{5} \cdot 2^\frac{1}{5} =2^1\]

OpenStudy (brooke..help00):

And 2 ^1 is the answer. ?

OpenStudy (phi):

yes, but because 2^1 is 2 we write it simply as 2

OpenStudy (brooke..help00):

Ok thanks! I have a few more can u help[?

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