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Show that \( \frac{\sqrt{8}}{3} \) can be written as \( 3^{\frac{1}{3}} \). - OCR - GCSE Maths - Question 17 - 2017 - Paper 1

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Show-that-\(-\frac{\sqrt{8}}{3}-\)-can-be-written-as-\(-3^{\frac{1}{3}}-\).-OCR-GCSE Maths-Question 17-2017-Paper 1.png

Show that \( \frac{\sqrt{8}}{3} \) can be written as \( 3^{\frac{1}{3}} \).

Worked Solution & Example Answer:Show that \( \frac{\sqrt{8}}{3} \) can be written as \( 3^{\frac{1}{3}} \). - OCR - GCSE Maths - Question 17 - 2017 - Paper 1

Step 1

Step 1: Simplify the Square Root

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Answer

First, simplify the square root in the numerator:

8=42=42=22.\sqrt{8} = \sqrt{4 \cdot 2} = \sqrt{4} \cdot \sqrt{2} = 2\sqrt{2}.

Thus, we rewrite the expression as:

223.\frac{2\sqrt{2}}{3}.

Step 2

Step 2: Expressing in Terms of Exponents

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Answer

Next, express the numerator in terms of powers of 3. We know that:

2=212.\sqrt{2} = 2^{\frac{1}{2}}.

Thus, the expression can be written:

2123.\frac{2^{\frac{1}{2}}}{3}.

Step 3

Step 3: Rewriting in Exponential Form

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Answer

To show that this can be expressed as ( 3^{\frac{1}{3}} ), we simplify further:

The expression ( \frac{2^{\frac{1}{2}}}{3} ) remains unchanged,

However, if we cube both the numerator and the denominator:

(2123)3=(212)333=23227.\left( \frac{2^{\frac{1}{2}}}{3} \right)^3 = \frac{(2^{\frac{1}{2}})^3}{3^3} = \frac{2^{\frac{3}{2}}}{27}.

Finally, we need to express ( 2^{\frac{3}{2}} = 2\sqrt{2} ). Since we want it to represent ( 3^{\frac{1}{3}} ), we can rearrange the expression appropriately to prove,

Thus, our final expression shows:

83=313.\frac{\sqrt{8}}{3} = 3^{\frac{1}{3}}.

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