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By rationalising the denominator of eac...

By rationalising the denominator of each of the following : Find in each case, the value correct to two significant figures :
` (4)/(3sqrt2-2sqrt3) `

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To solve the problem of rationalizing the denominator of \(\frac{4}{3\sqrt{2} - 2\sqrt{3}}\) and finding the value correct to two significant figures, we can follow these steps: ### Step 1: Identify the rationalizing factor The denominator is \(3\sqrt{2} - 2\sqrt{3}\). To rationalize it, we multiply by the conjugate, which is \(3\sqrt{2} + 2\sqrt{3}\). ### Step 2: Multiply the numerator and denominator by the rationalizing factor We have: \[ \frac{4}{3\sqrt{2} - 2\sqrt{3}} \cdot \frac{3\sqrt{2} + 2\sqrt{3}}{3\sqrt{2} + 2\sqrt{3}} = \frac{4(3\sqrt{2} + 2\sqrt{3})}{(3\sqrt{2} - 2\sqrt{3})(3\sqrt{2} + 2\sqrt{3})} \] ### Step 3: Simplify the denominator Using the difference of squares formula \( (A - B)(A + B) = A^2 - B^2 \): - Here, \(A = 3\sqrt{2}\) and \(B = 2\sqrt{3}\). - So, the denominator becomes: \[ (3\sqrt{2})^2 - (2\sqrt{3})^2 = 9 \cdot 2 - 4 \cdot 3 = 18 - 12 = 6 \] ### Step 4: Expand the numerator Now, simplify the numerator: \[ 4(3\sqrt{2} + 2\sqrt{3}) = 12\sqrt{2} + 8\sqrt{3} \] ### Step 5: Combine the results Now we have: \[ \frac{12\sqrt{2} + 8\sqrt{3}}{6} \] This can be simplified by dividing each term in the numerator by 6: \[ = 2\sqrt{2} + \frac{4\sqrt{3}}{3} \] ### Step 6: Substitute the approximate values of \(\sqrt{2}\) and \(\sqrt{3}\) Using the approximate values: - \(\sqrt{2} \approx 1.414\) - \(\sqrt{3} \approx 1.732\) Substituting these values: \[ 2\sqrt{2} + \frac{4\sqrt{3}}{3} \approx 2(1.414) + \frac{4(1.732)}{3} \] Calculating each term: \[ 2(1.414) \approx 2.828 \] \[ \frac{4(1.732)}{3} \approx \frac{6.928}{3} \approx 2.309 \] Adding these together: \[ 2.828 + 2.309 \approx 5.137 \] ### Step 7: Round to two significant figures Rounding \(5.137\) to two significant figures gives us \(5.14\). ### Final Answer The value of \(\frac{4}{3\sqrt{2} - 2\sqrt{3}}\) after rationalizing the denominator and rounding to two significant figures is: \[ \boxed{5.14} \]
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