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Mathematics

Find the values of 'a' and 'b':

2+323=a+b3\dfrac{2 + \sqrt{3}}{2 - \sqrt{3}} = a + b\sqrt{3}

Rational Irrational Nos

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Answer

Given,

Equation : 2+323=a+b3\dfrac{2 + \sqrt{3}}{2 - \sqrt{3}} = a + b\sqrt{3}

Rationalizing L.H.S. of the above equation :

2+323×2+32+3(2+3)222(3)222+(3)2+2×2×322(3)24+3+43437+43.\Rightarrow \dfrac{2 + \sqrt{3}}{2 - \sqrt{3}} \times \dfrac{2 + \sqrt{3}}{2 + \sqrt{3}} \\[1em] \Rightarrow \dfrac{(2 + \sqrt{3})^2}{2^2 - (\sqrt{3})^2} \\[1em] \Rightarrow \dfrac{2^2 + (\sqrt{3})^2 + 2 \times 2 \times \sqrt{3}}{2^2 - (\sqrt{3})^2} \\[1em] \Rightarrow \dfrac{4 + 3 + 4\sqrt{3}}{4 - 3} \\[1em] \Rightarrow 7 + 4\sqrt{3}.

Comparing 7+43 with a+b37 + 4\sqrt{3} \text{ with } a + b\sqrt{3}, we get :

a = 7 and b = 4.

Hence, a = 7 and b = 4.

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