If $x = 3 + 2\sqrt{2}$,then find the value of $x^{2} + \frac{1}{x^{2}}$ and $x^{3} + \frac{1}{x^{3}}$.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) Given $x = 3 + 2\sqrt{2}$.
First,find $\frac{1}{x}$:
$\frac{1}{x} = \frac{1}{3 + 2\sqrt{2}} = \frac{1}{3 + 2\sqrt{2}} \times \frac{3 - 2\sqrt{2}}{3 - 2\sqrt{2}} = \frac{3 - 2\sqrt{2}}{9 - 8} = 3 - 2\sqrt{2}$.
Now,calculate $x + \frac{1}{x}$:
$x + \frac{1}{x} = (3 + 2\sqrt{2}) + (3 - 2\sqrt{2}) = 6$.
To find $x^{2} + \frac{1}{x^{2}}$,use the identity $(x + \frac{1}{x})^{2} = x^{2} + \frac{1}{x^{2}} + 2$:
$x^{2} + \frac{1}{x^{2}} = (x + \frac{1}{x})^{2} - 2 = (6)^{2} - 2 = 36 - 2 = 34$.
To find $x^{3} + \frac{1}{x^{3}}$,use the identity $(x + \frac{1}{x})^{3} = x^{3} + \frac{1}{x^{3}} + 3(x + \frac{1}{x})$:
$x^{3} + \frac{1}{x^{3}} = (x + \frac{1}{x})^{3} - 3(x + \frac{1}{x}) = (6)^{3} - 3(6) = 216 - 18 = 198$.
Thus,the values are $34$ and $198$.

Explore More

Similar Questions

Rationalise the denominators of the following:
$(i)$ $\frac{1}{\sqrt{7}}$
$(ii)$ $\frac{1}{\sqrt{7}-\sqrt{6}}$
$(iii)$ $\frac{1}{\sqrt{5}+\sqrt{2}}$
$(iv)$ $\frac{1}{\sqrt{7}-2}$

Simplify: $\frac{7 \sqrt{3}}{\sqrt{10}+\sqrt{3}}-\frac{2 \sqrt{5}}{\sqrt{6}+\sqrt{5}}-\frac{3 \sqrt{2}}{\sqrt{15}+3 \sqrt{2}}$

Difficult
View Solution

Rationalise the denominator in each of the following:
$\frac{1}{7-4 \sqrt{3}}$

Classify the following numbers as rational or irrational:
$(i)$ $2-\sqrt{5}$
$(ii)$ $(3+\sqrt{23})-\sqrt{23}$
$(iii)$ $\frac{2 \sqrt{7}}{7 \sqrt{7}}$
$(iv)$ $\frac{1}{\sqrt{2}}$
$(v)$ $2 \pi$

The value of $\frac{\sqrt{32}+\sqrt{48}}{\sqrt{8}+\sqrt{12}}$ is equal to

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo