If $x+y=2$ and $\frac{1}{x}+\frac{1}{y}=\frac{18}{5}$, then the value of $\left(x^3+y^3\right)$ is: |
$4 \frac{2}{3}$ $4 \frac{3}{5}$ $3 \frac{1}{5}$ $3 \frac{1}{3}$ |
$4 \frac{2}{3}$ |
If $x+y=2$ $\frac{1}{x}+\frac{1}{y}=\frac{18}{5}$ $\frac{x + y}{xy}=\frac{18}{5}$ $\frac{2}{xy}=\frac{18}{5}$ xy = $\frac{5}{9}$ The value of $\left(x^3+y^3\right)$ = If x + y = n then, $x^3 + y^3$ = n3 - 3 × n × xy $x^3 + y^3$ = 23 - 3 × 2 × $\frac{5}{9}$ = $x^3 + y^3$ = 8 - $\frac{10}{3}$ $x^3 + y^3$ = $4 \frac{2}{3}$ |