If x=(sqrt(3)-sqrt(2))/(sqrt(3)+sqrt(2)) and y=(sqrt(3)+sqrt(2))/(sqrt(3)-sqrt(2)), then the value of x^3 + y^3 is: (a) 950 (b) 730 (c) 650 (d) 970
Calculation of the Given Expression Given the equation \(a^{2}+b^{2}=5ab\), we are tasked with determining the value of the expression \(\left(\frac{a^{2}}{b^{2}}+\frac{b^{2}}{a^{2}}\right)\). Step 1: Simplify the Given Relation Starting with the given equation, we divide both sides by \(ab\) to simRead more
Calculation of the Given Expression
Given the equation \(a^{2}+b^{2}=5ab\), we are tasked with determining the value of the expression \(\left(\frac{a^{2}}{b^{2}}+\frac{b^{2}}{a^{2}}\right)\).
Step 1: Simplify the Given Relation
Starting with the given equation, we divide both sides by \(ab\) to simplify:
\[
\frac{a^2 + b^2}{ab} = 5
\]
This leads to:
\[
\frac{a}{b} + \frac{b}{a} = 5
\]
Step 2: Square Both Sides
To find the value of \(\left(\frac{a^{2}}{b^{2}}+\frac{b^{2}}{a^{2}}\right)\), we square both sides of the simplified equation:
\[
\left(\frac{a}{b} + \frac{b}{a}\right)^2 = 5^2
\]
This yields:
\[
\frac{a^2}{b^2} + 2\left(\frac{a}{b}\cdot\frac{b}{a}\right) + \frac{b^2}{a^2} = 25
\]
Given that \(\frac{a}{b}\cdot\frac{b}{a} = 1\), we simplify further:
\[
\frac{a^2}{b^2} + \frac{b^2}{a^2} + 2 = 25
\]
Step 3: Isolate the Target Expression
Subtracting 2 from both sides to isolate the expression gives us:
\[
\frac{a^2}{b^2} + \frac{b^2}{a^2} = 25 – 2 = 23
\]
Conclusion
Therefore, the value of the expression \(\left(\frac{a^{2}}{b^{2}}+\frac{b^{2}}{a^{2}}\right)\) is \(\textbf{23}\), making the correct answer:
(c) \(\textbf{23}\)
This solution methodically derives the value of the given expression by leveraging the initial condition and algebraic manipulation, leading to a clear and logical conclusion.
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Evaluation of \(x^3 + y^3\) Given \(x\) and \(y\) For the given values of \(x\) and \(y\), defined as: \[x=\frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}+\sqrt{2}}\] \[y=\frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}\] We aim to find the value of \(x^3 + y^3\). Step 1: Simplify \(x\) and \(y\) First, rationalize \(Read more
Evaluation of \(x^3 + y^3\) Given \(x\) and \(y\)
For the given values of \(x\) and \(y\), defined as:
\[x=\frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}+\sqrt{2}}\]
\[y=\frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}\]
We aim to find the value of \(x^3 + y^3\).
Step 1: Simplify \(x\) and \(y\)
First, rationalize \(x\) by multiplying the numerator and denominator by the conjugate of the denominator:
\[
x=\frac{(\sqrt{3}-\sqrt{2})^2}{(\sqrt{3}+\sqrt{2})(\sqrt{3}-\sqrt{2})} = \frac{3 – 2\sqrt{6} + 2}{1} = 5 – 2\sqrt{6}
\]
Using a similar process for \(y\), we rationalize by multiplying by the conjugate, yielding:
\[
y=\frac{(\sqrt{3}+\sqrt{2})^2}{(\sqrt{3}-\sqrt{2})(\sqrt{3}+\sqrt{2})} = 5 + 2\sqrt{6}
\]
Step 2: Calculate \(x+y\)
Adding \(x\) and \(y\) gives us:
\[
x+y = (5 – 2\sqrt{6}) + (5 + 2\sqrt{6}) = 10
\]
Step 3: Calculate \(xy\)
Multiplying \(x\) and \(y\) provides:
\[
xy = (5 – 2\sqrt{6})(5 + 2\sqrt{6}) = 25 – (2\sqrt{6})^2 = 25 – 24 = 1
\]
Step 4: Derive \(x^3 + y^3\)
Using the identity \(x^3 + y^3 = (x + y)^3 – 3xy(x + y)\) and substituting the calculated values:
\[
x^3 + y^3 = 10^3 – 3 \cdot 1 \cdot 10 = 1000 – 30 = 970
\]
Conclusion
The value of \(x^3 + y^3\) is 970, corresponding to:
(d) 970
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